List of contaminated cell lines

Many cell lines that are widely used for biomedical research have been overgrown by other, more aggressive cells. For example, supposed thyroid lines were actually melanoma cells, supposed prostate tissue was actually bladder cancer, and supposed normal uterine cultures were actually breast cancer.^[1]

This is a list of cell lines that have been cross-contaminated and overgrown by other cells. A project is currently underway to enumerate and rename contaminated cell lines to avoid errors in research caused by misattribution (Masters, 2002). Estimates based on screening of leukemia-lymphoma cell lines suggest that about 15% of these cell lines are not representative of what they are usually assumed to be (Drexler et al., 2002).

Contaminated cell lines have been extensively used in research without knowledge of their true character. For example, most if not all research on the endothelium ECV-304 or the megakaryocyte DAMI cell lines has in reality been conducted on bladder carcinoma and erythroleukemia cells, respectively. Thus, all research on endothelium- or megakaryocyte-specific functions utilizing these cell lines has turned out to be misguided, serving more of a warning example.

There are two principal ways a cell line can become contaminated: cell cultures are often exchanged between research groups; if, during handling, a sample gets contaminated and then passed on, subsequent exchanges of cells will lead to the contaminating population being established, although parts of the supposed cell line are still genuine. More serious is contamination at the source: during establishment of the original cell line, some contaminating cells are accidentally introduced into the cultures, where they in time outgrow the desired cells. The initial testing, in this case, still suggested that the cell line is genuine and novel, but in reality, it has disappeared soon after being established and all samples of such cell lines are actually the contaminant cells. It requires lengthy research to determine the precise point where cell lines have become contaminated. A mix-up rated as contamination could in reality be a simple confusion of two cell lines, but usually contamination is assumed.

Cell lines marked Virtual in the table below are known instances of contamination at the source; these cell lines became extinct or never existed. Cases where non-contaminated lines are known or strongly suspected to exist are marked Existent.

Contaminated cell lines should never be used for research demanding the specific type of cell line they are assumed to be, and most of them should ideally be discarded or at least not used in research at all, except when the contaminant cells have acquired novel characteristics (e.g., by mutation or viral transfection, for example the HeLa derivate Det98) and thus constitute a novel lineage after all.

If in doubt, researchers should test cell lines for authenticity; the references listed below contain some papers on how common contaminants can be recognized. It is worth noting that the widespread contamination with HeLa cells was initially recognized by Walter Nelson-Rees using simple Giemsa stain karyotyping under a light microscope. This technique works well in recognizing HeLa because these cells have distinctive chromosome aberrations.

Novel cell lines should be proliferated and distributed and/or deposited at a safekeeping institution such as the ATCC as soon as possible after establishment, to minimize the odds that the line becomes spoiled by contamination. It is good practice to periodically check cell lines maintained under laboratory conditions (i.e., not placed in long-term storage) for contamination with HeLa or other common contaminants, to ensure that their quality and integrity is maintained.

Lists of contaminated cell lines

An updated list can be obtained from International Cell Line Authentication Committee website.^[2] The list, last updated on December 1, 2016, has 488 cell lines.

Cellosaurus also is maintaining a list of "problematic" cell lines.^[3] The list is dynamically generated from all cell lines in the database with a comment containing the dedicated words "Problematic cell line". As of 17 January 2017 the list contained 757 entries.

If no species is given in the individual entries of the following tables, the table's species applies to both the assumed and the actual cell types.

References

Citations

Bibliography

• Chen, T. R. (1988): Re-evaluation of HeLa, HeLa S3, and Hep-2 karyotypes. Cytogenetics and Cell Genetics 48: 19-24. HTML abstract
• Dirks, Willy G.; MacLeod, Roderick A. F. & Drexler, Hans G. (1999): ECV304 (endothelial) is really T24 (bladder carcinoma): cell line cross-contamination at source. In Vitro Cellular & Developmental Biology 35: 558–559.
• Drexler, Hans G.; Dirks, Willy G. & MacLeod, Roderick A. F. (1999): False human hematopoietic cell lines: cross-contaminations and misinterpretations. Leukemia 13: 1601–1607. HTML abstract
• Drexler, Hans G.; MacLeod, Roderick A. F. & Dirks, Willy G. (2001): Cross-contamination: HS-Sultan is not a myeloma but a Burkitt lymphoma cell line. Blood 98: 3495–3496. PDF fulltext
• Drexler, Hans G.; Quentmeier, H.; Dirks, Willy G.; Uphoff, Cord C. & MacLeod, Roderick A. F. (2002a): DNA profiling and cytogenetic analysis of cell line WSU-CLL reveal cross-contamination with cell line REH (pre B-ALL). Leukemia 16: 1868–1870. doi:10.1038/sj.leu.2402610 (HTML abstract)
• Drexler, Hans G.; Uphoff, Cord C.; Dirks, Willy G. & MacLeod, Roderick A. F. (2002b): Mix-ups and mycoplasma: the enemies within. Leukemia Research 26: 329–333. doi:10.1016/S0145-2126(01)00136-9 (HTML abstract)
• Drexler, Hans G.; Dirks, Willy G.; Matsuo, Y. & MacLeod, Roderick A. F. (2003): False leukemia–lymphoma cell lines: an update on over 500 cell lines. Leukemia 17: 416–426. doi:10.1038/sj.leu.2402799 (HTML abstract) HTML partial fulltext
• Lacroix, Marc (2008): Persistent use of "false" cell lines. International Journal of Cancer 122: 1–4. doi:10.1002/ijc.23233 PMID 17960586 (HTML abstract)
• MacLeod, Roderick A. F.; Dirks, Willy G.& Drexler, Hans G. (1997a): Early Contamination of the Dami Cell Line by HEL. Blood 90: 2850-2851. PDF fulltext
• MacLeod, Roderick A. F.; Dirks, Willy G.; Reid, Y. A.; Hay, R. J. & Drexler, Hans G. (1997b): Identity of original and late passage Dami megakaryocytes with HEL erythroleukemia cells shown by combined cytogenetics and DNA fingerprinting. Leukemia 11: 2032–2038. HTML abstract
• MacLeod, Roderick A. F.; Dirks, Willy G.; Matsuo, Y.; Kaufmann, M.; Milch, H. & Drexler, Hans G. (1999): Widespread intraspecies cross-contamination of human tumor cell lines arising at source. International Journal of Cancer 83: 555-563. HTML abstract
• Masters, John R. (2002): HeLa cells 50 years on: the good, the bad and the ugly. Nature Reviews Cancer 2: 315-319. doi:10.1038/nrc775 (HTML abstract)
• Nelson-Rees, W. A. & Flandermeyer, R. R. (1976): HeLa cultures defined. Science 191: 96–98. HTML abstract
• Nelson-Rees, W. A.; Daniels, D. W. & Flandermeyer, R. R. (1981): Cross-contamination of cells in culture. Science 212: 446–452. doi:10.1126/science.6451928 (HTML abstract)
• Unger, Ronald E.; Krump-Konvalinkova, V.; Peters, K. & Kirkpatrick, C. J. (2002): In Vitro Expression of the Endothelial Phenotype: Comparative Study of Primary Isolated Cells and Cell Lines, Including the Novel Cell Line HPMEC-ST1.6R. Microvascular Research 64: 384–397. Pubmed

External links

• Cellosaurus list of problematics (contaminated/misidentified) cell lines