StemCell Medicine

The board of the California stem cell agency has endorsed a public option as part of the national health care insurance reform effort, a move that a backer said would help with affordable access to any stem cell therapies developed with taxpayer funds.The board took the position last week on a motion by director Jeff Sheehy, a communications manager for UC San Francisco. He sits on the board as a

International Stem Cell Corporation respectfully requests that the NIH grant to researchers using stem cells created through parthenogenesis the same access to Federal funding as is provided for embryonic stem cells.

The fundamental basis for our request is that, although parthenogenetic stem cells are derived from unfertilized human eggs, not human embryos, the currently proposed Guidelines are likely to be interpreted to prohibit funding for such lines, even though the donation procedures otherwise meet all the requirements being imposed on embryonic stem cells.

Both types of cell lines are derived from human eggs obtained in the normal process of in-vitro fertilization. The difference is that making embryonic stem cells requires the creation (by fertilization) and subsequent destruction of viable human embryos, while parthenogenesis requires only unfertilized eggs from which no viable embryo is ever created or destroyed.

If parthenogenesis is denied funding, the source of stem cell lines that raises the fewest ethical issues (parthenogenesis) would be denied funding while the source that raises the most (embryonic stem cells) would receive Federal funding. Of possibly greater importance is the fact that while the stem cell industry is still in its infancy, with none of the hopes for embryonic, iPS or any other cell types yet verified in the clinic, the arbitrary exclusion from funding of an alternate technology that might offer new solutions could result in wasted opportunities to save human lives.

Both types of cell lines are obtained from eggs donated by women who have already made the decision to seek in-vitro fertilization. The primary motives of the donors are the same, and the consent procedures and donor protections are also the same. No public purpose is served by excluding parthenogenic stem cell lines from federal funding simply because the donated eggs were not fertilized in the process of creating stem cells.
Based on these distinctions, we propose that so long as the primary motivation of the donors is the same and the same ethical and informed consent standards are applied, whether or not excess eggs from IVF clinics are fertilized or not fertilized should not affect whether they may be used for federally sponsored research.

We suggest that the following factors also be considered in determining the final form of the Guidelines:

· The fear that viable human embryos are being created solely for research purposes or that women are being exploited for their eggs simply does not apply to parthenogenesis. First, as mentioned above, parthenogenesis does not lead to the creation of viable human embryos. No potential human life is destroyed. Second, the existing parthenogenetic stem cell lines were created from eggs donated by women with the primary intent of participating in IVF, and the same standard can and should be maintained for future lines. Whether excess eggs are fertilized or unfertilized does not pose any additional risk to the donors. In fact, every woman who has ever donated eggs to our company that led to the creation of parthenogenetic stem cell lines has had a successful pregnancy.

· Parthenogenesis may actually reduce the number of donations required because it allows for the creation of single lines of pluripotent stem cells that can be immune-matched (similar to how bone marrow is matched between donors and recipients) to large population groups. In other words, once a stem cell bank of perhaps 50 to 100 parthenogenetic stem cell lines is established, the need to continuously seek more eggs to match a population group may be greatly reduced or eliminated. The resulting immune-matched stem cell bank would become a valuable medical resource for regenerative medicine that is not available from any other source of cells. As a result, the total number of unfertilized eggs needed to create such a stem cell bank may be far fewer than the number of viable human embryos needed under the currently proposed Guidelines.

· The proposed Guidelines could create an unintended de-facto monopoly on the economic benefits of stem cell research. Today, a small number of organizations and companies control most of the current patents for embryonic cells. If cells subject to those patents are the only cells that can receive Federal funding, there will be no competition in the licensing of patents and no incentive for lower cost licensing of those rights. This could easily increase the cost of cures to the patient or repress innovation. Allowing alternative methods of creating stem cells, so long as they comply with the ethical rules of informed consent and utilize only appropriate donors, could avoid those problems.

· Blocking access to Federal funding for alternative methods of stem cell research could limit research opportunities for NIH-based scientists and also drive research and jobs overseas. Due to their unique characteristics, parthenogenetic stem cells offer a valuable research model to study immune response, cell differentiation and epigenetic processes such as imprinting, methylation, reprogramming and maternal effects. Under the proposed Guidelines, this research model would not be available to NIH-funded researchers in the U.S. U.S. companies now developing parthenogenesis technology are already receiving offers from various foreign countries such as Korea, India, and China to provide funding and move research to those countries. Without access to federal dollars, there will be no practical imperative to prevent U.S. companies from locating overseas. If disease cures are then developed outside the U.S., the potential profits and jobs will go elsewhere and the cures developed could come back to the U.S. at a much higher price.

We appreciate this opportunity to make our comments public, make ourselves available to the Institute for consultation on issues relating to stem cell research, and look forward to a rigorous review process prior to the finalization of the Institute’s guidelines.

Sincerely,
Kenneth C. Aldrich
Chairman, CEO, and Co-Founder
International Stem Cell Corporation

In light of recent comments made by International Stem Cell in response to the NIH proposed Guidelines, I have been asked a lot of questions. Let me try to answer a few of the most common ones.

Q: Will the proposed guidelines hurt International Stem Cell unless they are revised?

A: No. They will be an inconvenience and perhaps force us to accept funding from foreign instead of US sources, but will not change the fundamental prospects of our company at all. We have been operating under the same kind of restrictions since the founding of our company and can continue to do so. NIH funding is of far more importance to academic researchers than to companies and a change specifically permitting Federal funding for Parthenogenesis research would enable more researchers in the US to use our cells. That would enable us perhaps to do more of our work here at home, but we truly are an international company and expect to be able to obtain the kind of funded research and researchers even if the proposed rules are not changed. However, we would greatly prefer to develop our technology with US based scientists in US universities if possible.

Q: Why then are you so opposed to the present proposed Guidelines?

A: The present proposals specifically exclude the use of Parthenogenesis (our technology) and SCNT (technology that we have licensed but do not currently use). Both of these are potentially very valuable sources of cells for the treatment of human diseases and can do things that can’t be done with Embryonic stem cells or the iPS cells that are derived from genetically re-programmed human tissue. For example, parthenogenetic stem cells can be matched to the immune systems of millions of individuals, thus allowing the efficient creation of true stem cell banks for the population. Different stem cell technologies increase the potential for new medical breakthroughs and we believe that parthenogenesis is the strongest technology with the most medical potential. If the US government restricts the kind of technology it will support, whether because of politics or ignorance of the facts, it could deprive millions of people of the benefit of cures that might otherwise have been discovered.

Q: Why do you think the NIH has restricted its funding in these Guidelines?

A: I believe there are several issues, but none of them apply for Parthenogenesis. The NIH does not want federal money spent to derive human embryos for research use only. This does not apply for Parthenogenesis, because Parthenogenesis requires unfertilized human eggs – not fertilized human embryos. We believe this places Parthenogenesis on higher ethical ground. In addition, all of our Parthenogenetic lines have been created by women who entered IVF clinics with the intent of undergoing in-vitro fertilization (IVF), not the intent of creating stem cell lines.

I can only speculate, but strongly suspect that an additional reason may be a fear that somehow these technologies will lead to the need for thousands of human eggs and that women donors will be abused or taken advantage of to obtain such eggs for research. Nothing could be farther from the truth. The reality is that Parthenogenetic stem cells are derived from the excess eggs that fertilization clinics will eventually throw away. The only relevant difference between how stem cells are created through Parthenogenesis and how embryonic stem cells are created is whether or not the eggs are fertilized before being used as a source of stem cells. That has no impact on the donor at all. She produces the same number of eggs in the same way and only the excess are used for research, all under the same kinds of consent regulations. In addition, Parthenogenesis is an efficient process and does not require large numbers of eggs to produce a stem cell line. In fact, because Parthenogenesis can create a single line from a single donor that can be immune-matched to millions of individuals from multiple racial groups, once a bank of these lines is created, the need to obtain more human eggs will be greatly diminished or eliminated.

I hope these comments will clear up some of the mystery.
Sincerely,

Kenneth Aldrich
Chairman & CEO
International Stem Cell Corporation (ISCO.OB)
760-940-6383 (corporate office)
310-454-3055 (direct line)
310-593-1180 (mobile)
kaldrich@intlstemcell.com
www.internationalstemcell.com

International Stem Cell Corporation’s Chairman and CEO, Kenneth Aldrich will speak at the 3rd International Congress of NanoBiotechnology and Nanomedicine (NanoBio 2009) on June 23, 2009. Mr. Aldrich’s presentation is entitled, “Stem Cells and Nanotechnology: Marriage or Myth”. The conference will take place in San Francisco from June 22-24, 2009 www.ianano.org.

International Stem Cell Corporation (OTCBB:ISCO), has entered into a definitive agreement for a $5 million investment commitment (the “Investment”) with a biotechnology-focused fund (the “Investor”) that has offices in New York and California. The Investment will be used to fund operations and working capital needs of the company and expand its scientific research. Proceeds of the investment provide a valuable addition to the company’s capital structure. Together with the private capital already committed to the company and its internally generated revenue, these funds are expected to provide the capital needed by ISCO for the balance of 2009 and a significant amount of the capital expected to be needed in 2010.

The Company may draw down funds from the Investor as it finds a need, but is not obligated to do so. Funds will be drawn down through the issuance of Series E Preferred Stock (the “Preferred Stock”). The Preferred Stock will not be convertible into common stock and may be redeemed by the Company after one year. Each issue of Preferred Stock will be accompanied by the issuance of five-year warrants to purchase common stock at 100% of the closing price of the company’s common stock on the day prior to the date the company gives notice of its election to draw funds. The total exercise value of warrants issued will equal 135% of the drawdown amount. Dividends on the Preferred Stock are payable in additional shares of non-convertible Preferred Stock at the rate of 10% per annum. A commitment fee of $250,000, payable in shares of common stock, was made to the Investor.

“The flexibility of this financing will add greatly to our financial strength,” commented Kenneth Aldrich, CEO and Chairman of ISCO. “We are pleased that we have secured a financing source that will be available to us at the time of our own choosing over the next year.”

For more news and information on International Stem Cell Corporation please visit www.IRGnews.com/coi/ISCO where you can find the CEO’s video, a fact sheet on the company, investor presentations, and more.

ABOUT INTERNATIONAL STEM CELL CORPORATION (ISCO.OB):

International Stem Cell Corporation is a California biotechnology company focused on developing therapeutic and research products. ISCO’s technology, Parthenogenesis, results in the creation of pluripotent human stem cell lines from unfertilized human eggs. ISCO scientists have created the first Parthenogenetic homozygous stem cell line (phSC-Hhom-4) that can be a source of therapeutic cells that will minimize immune rejection after transplantation into hundreds of millions of individuals of differing sexes, ages and racial groups. These advancements offer the potential to create the first true “Stem Cell Bank” and address ethical issues by eliminating the need to use or destroy fertilized embryos. ISCO also produces and markets specialized cells and growth media worldwide for therapeutic research through its subsidiary Lifeline Cell Technology. For more information, visit the ISCO website at: www.internationalstemcell.com.

To subscribe to receive ongoing corporate communications please click on the following link: http://www.b2i.us/irpass.asp?BzID=1468&to=ea&s=0.

FORWARD-LOOKING STATEMENTS:

Statements pertaining to anticipated future financial and/or operating results, future growth in research, technology, clinical development and potential joint venture and other opportunities for the company and its subsidiary, along with other statements about the future expectations, beliefs, goals, plans, or prospects expressed by management constitute forward-looking statements. Any statements that are not historical fact (including, but not limited to statements that contain words such as “will,” “believes,” “plans,” “anticipates,” “expects,” “estimates”) should also be considered to be forward-looking statements. Forward-looking statements involve risks and uncertainties, including, without limitation, risks inherent in the development and/or commercialization of potential products, uncertainty in the results of clinical trials or regulatory approvals, need and ability to obtain future capital, application of capital resources among competing uses, and maintenance of intellectual property rights. Actual results may differ materially from the results anticipated in these forward-looking statements and as such should be evaluated together with the many uncertainties that affect the company’s business, particularly those mentioned in the cautionary statements found in the company’s Securities and Exchange Commission filings. The company disclaims any intent or obligation to update these forward-looking statements.

Key Words: Stem Cells, Biotechnology, Parthenogenesis

International Stem Cell Corporation
Kenneth C. Aldrich, Chairman, CEO
760-940-6383
kaldrich@intlstemcell.com
or
The Investor Relations Group
212-825-3210
Investor Relations:
Adam S. Holdsworth
aholdsworth@investorrelationsgroup.com
or
Media Relations:
Laura Colontrelle
lcolontrelle@investorrelationsgroup.com

International Stem Cell Corporation (OTCBB:ISCO) has expanded its senior management team to include greater capacity and flexibility as it expands its therapeutic and commercial activities for the remainder of 2009 and beyond.

Professor Andrei Semetchkine, Ph.D., who is already a director and officer of the Company, will assume the duties of Executive Vice President of ISCO, with broad responsibility for the strategy, financial, and business affairs of the company. Dr. Semetchkine, a resident of Southern California, has been for many years a member of the prestigious Russian Academy of Sciences, the highest scientific body in Russia, and has been a founder or senior executive of many international businesses. “Dr. Semetchkine brings a depth of management skills, knowledge of opportunities in international science and a world experience that will be extremely valuable to our Company in the days to come,” said Kenneth Aldrich, Chairman, President and CEO of ISCO.

Jeffrey Janus, will continue to be CEO and President of Lifeline Cell Technology, the revenue generating subsidiary of ISCO, and will also serve as Senior Vice President of Operations for the parent Company, ISCO. “As ISCO and Lifeline have grown, the demands have increased,” said Mr. Janus. “The addition of Dr. Semetchkine to the senior management of ISCO will add tremendous strength to our strategic planning and management capabilities as we move forward towards therapeutic use of our parthenogenetic stem cells and to help us manage the expansion of both ISCO and Lifeline more effectively.”

In a final change, Ray Wood, who had been the controller of the company, has been promoted to Vice President, Finance and Principal Financial Officer. Mr. Wood has extensive public and private company experience that is expected to enhance ISCO’s financial and accounting strength.

Mr. Wood’s appointment will also permit William Adams, a founder of the Company to step down from his role as CFO as of June 30, 2009. He will now work full time on developing new capital sources and collaborative opportunities for the Company. Mr. Adams is responsible for much of the company’s financing to date, and this change will allow him to focus more effectively on future needs of the Company, particularly in establishing new industry and research collaborations. Mr. Adams has also elected to resign from the Board of Directors, effective June 30, 2009, and will assist the Company in seeking an outside Board member with relevant industry and regulatory affairs experience to fill the vacant seat. “I am by no means leaving the Company,” said Mr. Adams. “I am just refocusing my efforts where I believe I can be of the greatest help to the company’s future.”

For more news and information on International Stem Cell Corporation please visit www.IRGnews.com/coi/ISCO where you can find the CEO’s video, a fact sheet on the company, investor presentations, and more.

ABOUT INTERNATIONAL STEM CELL CORPORATION (ISCO.OB):

International Stem Cell Corporation is a California biotechnology company focused on developing therapeutic and research products. ISCO’s technology, Parthenogenesis, results in the creation of pluripotent human stem cell lines from unfertilized human eggs. ISCO scientists have created the first Parthenogenetic homozygous stem cell line (phSC-Hhom-4) that can be a source of therapeutic cells that will minimize immune rejection after transplantation into hundreds of millions of individuals of differing sexes, ages and racial groups. These advancements offer the potential to create the first true “Stem Cell Bank” and address ethical issues by eliminating the need to use or destroy fertilized embryos. ISCO also produces and markets specialized cells and growth media worldwide for therapeutic research through its subsidiary Lifeline Cell Technology. For more information, visit the ISCO website at: www.internationalstemcell.com.

To subscribe to receive ongoing corporate communications please click on the following link: http://www.b2i.us/irpass.asp?BzID=1468&to=ea&s=0.

FORWARD-LOOKING STATEMENTS:

Statements pertaining to anticipated future financial and/or operating results, future growth in research, technology, clinical development and potential joint venture and other opportunities for the company and its subsidiary, along with other statements about the future expectations, beliefs, goals, plans, or prospects expressed by management constitute forward-looking statements. Any statements that are not historical fact (including, but not limited to statements that contain words such as “will,” “believes,” “plans,” “anticipates,” “expects,” “estimates,”) should also be considered to be forward-looking statements. Forward-looking statements involve risks and uncertainties, including, without limitation, risks inherent in the development and/or commercialization of potential products, uncertainty in the results of clinical trials or regulatory approvals, need and ability to obtain future capital, application of capital resources among competing uses, and maintenance of intellectual property rights. Actual results may differ materially from the results anticipated in these forward-looking statements and as such should be evaluated together with the many uncertainties that affect the company’s business, particularly those mentioned in the cautionary statements found in the company’s Securities and Exchange Commission filings. The company disclaims any intent or obligation to update these forward-looking statements.

Key Words: Stem Cells, Biotechnology, Parthenogenesis

International Stem Cell Corporation
Kenneth C. Aldrich, Chairman, CEO
760-940-6383
kaldrich@intlstemcell.com
or
The Investor Relations Group
212-825-3210
Investor Relations:
Adam S. Holdsworth
aholdsworth@investorrelationsgroup.com
or
Media Relations:
Laura Colontrelle
lcolontrelle@investorrelationsgroup.com

Letter Describes Capital Funding, Strengthening of Senior Management Team, Agreement with Cytograft Tissue Engineering, Positive Results from Animal Trials, and Other Developments

International Stem Cell Corporation (OTCBB:ISCO), the first company to perfect a method of creating human stem cells from unfertilized eggs, has issued a letter to its shareholders. To view the shareholder letter in its entirety, please follow the link to the company’s website: http://www.internationalstemcell.com/shareholderletter.htm.

In the letter, International Stem Cell CEO and Chairman, Kenneth Aldrich updates shareholders on the company’s continued efforts to increase shareholder value related to its key initiatives and developments, which include:

* The Company continues to lead in the development of human parthenogenetic stem cell (“hpSC”) research. ISCO has made major strides in deriving cells that may be useful in the treatment of liver disease and in the creation of human corneal tissue both as a potential therapeutic product for corneal disease and as an alternative to animal testing to assess the safety of drugs and consumer products.

* $5 million investment commitment with a biotechnology-focused fund announced in July; funding expected to be in tranches, with first $1.5 million expected in September. Additional $1 million tranche funded on schedule under previously announced preferred stock offering, and over $500,000 in private common stock sales funded during first 6 months of 2009

* Senior management team strengthened to provide greater capacity and flexibility as company expands its therapeutic and commercial activities

* Positive early results reported in May from animal trials designed to improve photorefractive keratectomy (PRK), a form of corrective laser eye surgery that offers an improved alternative to LASIK

* March 2009 agreement with Cytograft Tissue Engineering to design custom cell culture medium to cultivate living human vascular grafts

“Viewed from a scientific, political, managerial, and financial perspective, the past six months have been a vibrant and compelling time in our corporate history,” says Mr. Aldrich. “The company remains committed to its vision of creating the means to manufacture, bank, and provide cells for patients that need them, on demand, at low cost, without the risk of immune rejection. We look forward to our shareholders reviewing this update, thank them for their steadfastness and support, and look forward to our shared work in the months and years ahead.”

ABOUT INTERNATIONAL STEM CELL CORPORATION (ISCO.OB)

International Stem Cell Corporation is a California biotechnology company focused on developing therapeutic and research products. ISCO’s technology, Parthenogenesis, results in the creation of pluripotent human stem cell lines from unfertilized human eggs. ISCO scientists have created the first Parthenogenetic homozygous stem cell line (phSC-Hhom-4) that can be a source of therapeutic cells that will minimize immune rejection after transplantation into hundreds of millions of individuals of differing sexes, ages and racial groups. These advancements offer the potential to create the first true “Stem Cell Bank” and address ethical issues by eliminating the need to use or destroy fertilized embryos. ISCO also produces and markets specialized cells and growth media worldwide for therapeutic research through its subsidiary Lifeline Cell Technology. For more information, visit the ISCO website at: www.internationalstemcell.com.

To subscribe to receive ongoing corporate communications please click on the following link: http://www.b2i.us/irpass.asp?BzID=1468&to=ea&s=0.

For more news and information on International Stem Cell Corporation please visit www.IRGnews.com/coi/ISCO where you can find the CEO’s video, a fact sheet on the company, investor presentations, and more.

FORWARD-LOOKING STATEMENTS:

Statements pertaining to expected future financial and/or operating results, anticipated funding, future research, technology and clinical development plans and potential opportunities for the company and its subsidiary, along with other statements about the future expectations, beliefs, goals, plans, or prospects expressed by management constitute forward-looking statements. Any statements that are not historical fact (including, but not limited to statements that contain words such as “will,” “believes,” “plans,” “anticipates,” “expects,” “estimates,”) should also be considered to be forward-looking statements. Forward-looking statements involve risks and uncertainties, including, without limitation, risks inherent in the completion of funding commitments, the development and/or commercialization of potential products, uncertainty in the results of clinical trials or regulatory approvals, need and ability to obtain future capital,and maintenance of intellectual property rights. Actual results may differ materially from the results anticipated in these forward-looking statements and as such should be evaluated together with the many uncertainties that affect the company’s business, particularly those mentioned in the cautionary statements found in the company’s Securities and Exchange Commission filings. The company disclaims any intent or obligation to update these forward-looking statements.

Key Words: Stem Cells, Biotechnology, Parthenogenesis

International Stem Cell Corporation
Kenneth C. Aldrich, Chairman, CEO
kaldrich@intlstemcell.com
760-940-6383
or
The Investor Relations Group
212-825-3210
Investor Relations:
Adam S. Holdsworth
aholdsworth@investorrelationsgroup.com
or
Media Relations:
Laura Colontrelle
lcolontrelle@investorrelationsgroup.com

Role of cancer stem cells in pancreatic ductal adenocarcinoma by Gregory Sergeant, Hugo Vankelecom, Lies Gremeaux and Baki Topal, Nat Rev Clin Oncol 2009(Aug 18) [Epub ahead of print]. PubMed Abstract:

As our understanding of pancreatic cancer evolves, evidence is growing to support a role for cancer stem cells in this devastating disease. Cancer stem cells constitute a distinct subpopulation in the tumor and are considered to drive both tumorigenesis and metastasis; these cells are thought to be highly resistant to standard treatment modalities. Here we review the current knowledge on pancreatic cancer stem cells and the implementation of cancer stem cell markers as prognostic or predictive biomarkers. We also discuss prospects for the use of cancer stem cells as targets for future therapeutic regimens in pancreatic cancer.

[Found via CSC-related articles bookmarked in Connotea].

Cancer stem cells spur hope, skepticism by Jill Colvin, The Globe and Mail, August 27, 2009. [WebCite cache][Twitter entry][FriendFeed entry]. Excerpt:

Ontario Cancer Institute researcher John Dick, arguably the world’s leading authority in the field, first identified stem cells in leukemia in the 1990s. Today, few doubt they play a key role in blood cancers.

In addition to this comment about the crucial contributions of John Dick, research on brain-tumour stem cells by Samuel Weiss is noted. There’s also mention of the MIT and Harvard joint venture, Identification of Selective Inhibitors of Cancer Stem Cells by High-Throughput Screening, published in Cell 2009(Aug 13). [See also this post in CSC News, August 14, 2009].

The criticisms by Scott Kern (such as: The fuzzy math of solid tumor stem cells: a perspective) of application the CSC hypothesis to colon, breast, or lung cancer are outlined. There’s also a comment attributed to Richard Hill:

The hypothesis also hinges on the assumption that these cells are rare. Otherwise, traditional cancer therapies that shrink tumours would be killing them, too, and there would be no need to develop specialized treatments.

The “game-changing paper” by a team led by Sean Morrison, Efficient tumour formation by single human melanoma cells is also discussed. [See another post in CSC News, December 3, 2008, about this paper]. This research supports the view that “… stem cells may be key for some kinds of cancers and not for others“.[This paper has attracted much attention. See, for example, Cancer Stem Cells May Not Be the Supervillains We Thought by Alexis Madrigal, Wired Science, December 3, 2008].

The article in The Globe & Mail ends with a paragraph about the hope that “new drug combinations that target all cell types” [associated with tumors] will be found, and a quote from William Hahn: “Whether the hypothesis is correct or incorrect in its full-blown beauty is really not important in the end” . [What really matters, from a clinical perspective, is whether or not efforts to target CSCs, in addition to other kinds of cells associated with tumors, will lead to improved outcomes for patients].

The article has already attracted some comments from readers.

Disclosure: I’m a co-author of some early papers about the CSC hypothesis, such as: J Natl Cancer Inst 1983(Jan); 70(1): 9-16.

New Type Of Adult Stem Cells Found In Prostate May Be Involved In Cancer Development, ScienceDaily, September 10, 2009. Excerpts:

The new study may resolve this conundrum because the newly discovered adult stem cells are also luminal cells. “Previous research suggested that prostate cancer originates from basal stem cells, and that during cancer formation these cells differentiate into luminal cells,” said Dr. Shen. “Instead, CARNs may represent a luminal origin for prostate cancer” [CARNs stands for "castration-resistant Nkx3.1-expressing cells"].

And indeed, the researchers found that CARNs in mice can give rise to prostate cancers, after the cells lose the activity of PTEN, a gene that is frequently mutated in human prostate cancers.

See also: New Progenitor Cell in Mice Can Cause Prostate Cancer, Michael Smith, Medpage Today, September 9, 2009; Researchers find prostate cancer stem cell, Reuters, September 9, 2009.

These news items are about the publication: A luminal epithelial stem cell that is a cell of origin for prostate cancer by Xi Wang and 9 co-authors, including Michael M Shen, Nature 2009(Sep 9) [Epub ahead of print][PubMed Citation].

Comment: These CSCs were found in mice, and “it is unclear whether CARNs exist in the normal human prostate and if human prostate cancers can originate from these CARNs” (see last paragraph of the Medpage Today article).

Found via: Two Studies Make Promising Advances in Prostate Cancer Research, Denis Cummings, FindingDulcinea, September 10, 2009.