Cell line authentication: a necessity for reproducible biomedical research

Abstract

Immortalized or continuous cell lines are invaluable tools in basic and preclinical research. However, the widespread use of misidentified cell lines is a serious threat to scientific reproducibility. Based on the experiences of mandatory cell line authentication at the International Journal of Cancer (IJC), we provide an overview of the issues pertinent to misidentified cell lines and discuss available solutions. We also summarize the lessons learned, revealing that at least 5% of the human cell lines used in manuscripts considered for peer review are misidentified. About 4% of the considered manuscripts are rejected for severe cell line problems, and most are subsequently published in other journals. In order to diminish such malpractice and its consequences for the scientific record, we postulate that strict multi-layered quality control is essential. Besides journals and publishers, we encourage scientists, research institutions, and funders to take action on the matter and revise their respective policies. Hence, we provide concrete recommendations on introducing regular authentication schemes and staff training, and discuss future steps for enhancing good cell culture practices.

Keywords: International Journal of Cancer; Cell line cross-contamination; good scientific practice; misidentified cell lines; research integrity.

Figure 1. Scenarios of data generation using cell lines as tumor models

The vast majority of scientific data are produced using authenticated cell lines, which generally reproduce well (blue area). Genetically unstable cell lines with highly heterogeneous populations may be subject to drift due to changing culture conditions (dashed arrows), making reproducible results difficult (light red area). Misidentified cell line model systems are most critical (red area) because reproducible data are virtually impossible to achieve. In the case of known misidentified cell lines, i.e., listed in the register of misidentified cell lines with no known authentic stock, generated data can be reproduced, but are meaningless.

Figure 2. Characteristics of the cell line problems observed in 747 manuscripts considered for peer review that included original human cell line data

1. A

   Different types and numbers of the 216 identified misidentified cell lines.

2. B

   The most frequently observed contaminants. A contaminant was reported as unknown if the contaminant was of non‐human origin, had a unique STR profile, was not reported, or not identified (i.e., SNP profiling).

3. C

   Percentages and numbers of misidentified cell lines grouped according to the tissue origin (number of misidentified cell lines/number of cell lines in total).

4. D

   Overview of the cell line‐related problems observed in the 747 manuscripts that were considered for peer review and included original human cell line data. Categories: Minor problems, e.g., minor textual adaptations; Moderate problems, e.g., one cell line had to be removed from the manuscript because it was misidentified; and Severe problems, e.g., at least two cell lines had to be removed from the manuscript because they were misidentified. See also Box 2.

5. E

   Recommendations of editorial measures to avoid publishing studies based on misidentified cell lines and to correct the contaminated published records.