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Notice for users of AZ521 cell line

We, the RIKEN BioResource Center, regret to inform you that AZ521 cell line (RCB2087) which we have previously provided as a human stomach cancer cell line was most likely to be a misidentified cell line of HuTu-80, a cell line of human duodenal cancer origin of American Type Culture Collection (ATCC). We understand that this misidentification of cell line might cause serious scientific damage. But, it is our hope that the damage is the minimum.

Please do not use AZ521 any more unless you have a compelling reason to keep using the cell line. Unfortunately, neither the depositor nor we have the original AZ521 cell line.

If you have published scientific papers using AZ521 cell line, please let us know. If you need, we will send a letter to an editor of a journal and explain the details of this misidentification.

AZ521 cell line was transferred as a cell line derived from human stomach cancer in 2004 from Tohoku University Cell Bank, one of cell banks in Japan. We had maintained and distributed AZ521 as a stomach cancer cell line since then. Most recently, we received a question from a Japanese scientist whether AZ521 was a misidentified cell line of HuTu-80 distributed of ATCC, similar to the case of AZ521 in Japanese Collection of Research Bioresources (JCRB) Cell Bank. Then, we examined the DNA profiling data of AZ521 in our Cell Bank and in JCRB Cell Bank and those of HuTu-80 (HTB-40) in their respective web sites. The DNA profiling data of AZ521 cell line in RIKEN BRC were completely identical to JCRB’ AZ521 and those of HuTu-80. Considering histories of AZT521 and HuTu-80, we concluded that AZ521 is most likely to be a misidentified cell line of HuTu-80. We decided to stop the provision of AZ521 cell line. The details of this misidentification are described below.

Please accept our sincere apologies and we beg your understanding.

If you want to use any other cell line from our cell bank at this time or in the future, we will provide you a cell line of your choice with free of charge. Please let me know.

We apologize again for sending you a misidentified cell line, although there was no way of knowing the misidentification at the time of distribution. We will do our best to distribute scientific community with authentic cell lines of the highest quality by DNA profiling and by supplying the most updated information regarding cell lines. We ask you for your understanding and continuous support.

If you have any question or request on this matter, please feel free to contact me.

With best regards,

Yukio NAKAMURA, M.D., Ph.D.
Cell Engineering Division (Cell Bank)
RIKEN BioResource Center (RIKEN BRC)
E-mail: cellqa.brcriken.jp

Misidentification of cell lines and STR polymorphism analysis
Cell lines are essential experimental materials in all fields of biology and are used in all kinds of experiments. However, misidentification of cell lines following cross contamination or replacement due to carelessness or inappropriate handling can occur through the routine and frequent use of cell lines. In spite of repeated warning, misidentification continues to occur at an extremely high rate (Ref. 1, 2). In the past, it was impossible to detect misidentification without a high through-put technology to detect differences among a large number of cell lines at the molecular level. Recently, the gene profiling of STR polymorphisms (STR profiling) was developed for forensic investigation and was subsequently established as a powerful method for the analysis of gene polymorphism. The STR profiling has been shown to be an efficient and reliable means of detecting misidentification of human cell lines (Ref. 3). Hence, authentication and standardization of cell lines are now possible using STR profiling (Ref. 4). At the moment, the major cell banks around the world including RIKEN BRC are collaborating to establish a common data base for the results of STR profiling (Ref. 5 and 6), although it is still in the beginning phase. Please refer to the following URL:

History of AZ521 cell line and its relation to HuTu-80
AZ521 cell line was established in Japan by Japanese scientists and a paper using AZ521 cell line was first published in 1985 (Ref. 7), and it was deposited to JCRB Cell Bank in 1985 and Tohoku University Cell Bank in 1991. As mentioned above, AZ521 cell line in Tohoku University Cell Bank was transferred to our Cell Bank in 2004, since Tohoku University decided to close its cell bank. At the time of transfer, the STR profiling revealed that AZ521 cell line was an independent cell line from all other human cell lines in our Cell Bank.

Meanwhile, HuTu-80 cell line was established in 1968 and deposited to ATCC in 1973. The first paper using HuTu-80 cell line was published in 1977 (Ref. 8). HuTu-80 cell line was established long before AZ521 and AZ521 had never been deposited to ATCC.

The results of STR profiling of RIKEN BRC Cell Bank’s AZ521 and JCRB’s AZ521 are completely identical, and also to those of HuTu-80. All these point out that AZ521 cell line is most likely to be a misidentified cell line of HuTu-80. It is most probable that the misidentification of AZ521 has occurred prior to the deposition to both Japanese cell banks, before 1985. However, neither the depositor nor the cell banks could possibly know how long before the deposition misidentification occurred.

A newly developed technology sometimes reveals mistake, mishandling, or misidentification that was made in the past and results in uncomfortable outcomes. Although the outcomes may be as painful as could be, we believe it is a necessary process for proper development of sciences. Through the unfortunate lessons in the past, the major cell banks around the world as the essential infrastructure for science are now collaborating for rigorous quality control of cell lines and establishment of database to serve better to the scientific community. We promise you we will make our best efforts to distribute cell lines of the best quality. We sincerely appreciate you for your continuous support and understanding of our activities.


  1. Cases of mistaken identity. Science 315: 928-931 (2007)
  2. Identity crisis. Nature 457: 935-936 (2009)
  3. Masters, J.R. et al. Short tandem repeat profiling provides an international reference standard for human cell lines. Proc Natl Acad Sci USA 98: 8012-8017 (2001)
  4. Yoshino, K. et al. Essential role for gene profiling analysis in the authentication of human cell lines. Hum Cell 19: 43-48 (2006)
  5. Katsnelson, A. Biologists tackle cells’ identity crisis. Nature 465: 537 (2010)
  6. Masters, J.R., et al. End the scandal of false cell lines. Nature 492: 186 (2012)
  7. Taki, T. et al., Immunological analysis of glycolipids on cell surfaces of cultured human tumor cell lines: expression of lactoneotetraosylceramide on tumor cell surfaces. J Biochem 98: 887-895 (1985)
  8. Schmidt, M. et al., Gastrointestinal cancer studies in the human to nude mouse heterotransplant system. Gastroenterology 72: 829-837 (1977)