# Cancel Culture in Cell Culture: A [Molecular Biology](/blog/careers/molecular-biology) Perspective


## Key Takeaways

- Cell line "cancellation" signifies a scientific determination that a cell line is no longer a valid model due to contamination or misidentification, rendering its data unreliable.
- Mycoplasma contamination, a prevalent issue, compromises cell line integrity by altering metabolism and gene expression, and is primarily detected via PCR targeting the 16S rRNA gene or luminescence-based ATP assays.
- Cross-contamination, particularly with the highly proliferative HeLa cell line, is a significant contributor to misidentification and is definitively identified through Short Tandem Repeat (STR) profiling, which acts as a genetic fingerprint.
- The International Cell Line Authentication Committee (ICLAC) registry serves as a critical resource for identifying and tracking cancelled cell lines, guiding researchers away from using compromised models.
- Preventing cancellation necessitates rigorous aseptic techniques, regular mycoplasma testing, and routine STR profiling for cell line authentication, especially upon receipt and before creating frozen stocks.
- Ignoring subtle changes in cell growth or assuming authenticity from reputable sources are common pitfalls that can lead to the use of cancelled cell lines, undermining research reproducibility.

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In the world of [molecular biology](/blog/careers/molecular-biology), the term "cancel culture" has taken on a meaning far removed from social media. When a scientist says a cell line has been "cancelled," they are not referring to a public shaming or a loss of followers. They are referring to a scientific judgment: the cell line is no longer trustworthy, no longer usable for experiments, and no longer accepted by the research community. This cancellation is not subjective. It is based on hard evidence—genetic fingerprints, contamination assays, and a trail of irreproducible results. For any student entering the life sciences, understanding why and how cell lines get cancelled is as fundamental as learning how to pipette. This article explains the molecular mechanisms behind cell line cancellation, the evidence that drives it, and the practical steps you can take to ensure your own cultures never end up on the cancellation list.

## What Is Cancel Culture in Cell Culture?

In everyday language, cancel culture refers to the collective decision to withdraw support from a person or organization. In cell culture, the concept is analogous but far more rigorous. A cell line is "cancelled" when the scientific community determines that it is no longer a valid model for the organism or tissue it claims to represent. This determination is made through objective, reproducible tests, and the consequence is severe: data generated from that cell line is considered unreliable, funding agencies may reject proposals that rely on it, and journals may refuse to publish studies that use it.

The cancellation of a cell line is not a casual decision. It is the end point of a process that begins with suspicion—often a researcher notices that their cells are behaving differently than expected—and culminates in molecular evidence. The evidence typically falls into one of two categories: contamination or misidentification. Contamination means that foreign cells or microorganisms have invaded the culture. Misidentification means that the cells in the flask are not the cells the label claims them to be. Both are grounds for cancellation.

### Origin of the Term

The term "cancelled" in this context emerged from the broader scientific conversation about the reproducibility crisis—the growing recognition that many published research findings cannot be replicated. [Cell line contamination](/knowledge/molecular-biology/cell-line-contamination) and misidentification are major contributors to this crisis. When a researcher unknowingly uses a contaminated cell line, their results are not about the intended cells at all. They are about whatever contaminant has taken over the culture. As the scientific community became more aware of this problem, the phrase "cancelled" entered the lexicon as a shorthand for "this cell line is no longer acceptable for research use." It is a blunt term, but it conveys the finality of the scientific judgment.

### Examples in Research

The most famous example of a cancelled cell line is the case of the "immortal" HeLa cells, which were derived from Henrietta Lacks in 1951. HeLa cells are not cancelled themselves—they are a legitimate and widely used tool. The problem is that HeLa cells are so robust and proliferative that they can contaminate other cell lines. A cell line that was supposed to be, say, a breast cancer line, might turn out to be HeLa cells that overgrew the original culture. When this is discovered, the contaminated line is cancelled.

Another example is the cell line known as "U87MG," which was long used as a model for glioblastoma, a type of brain cancer. In 2016, researchers at Uppsala University discovered that the U87MG line distributed by the American Type Culture Collection (ATCC) was not the original line established in 1966. The two lines had different genetic profiles. The ATCC version was cancelled as a model for the original tumor, and researchers had to re-evaluate years of published work that used it.

## The Mechanism of Cell Line Cancellation

A cell line becomes cancelled through a series of molecular events that compromise its identity or purity. Understanding these mechanisms is essential for anyone working in [Animal Cell Culture](/knowledge/molecular-biology/animal-cell-culture), because the same processes that cause cancellation are always at work in the laboratory. They are not rare events; they are constant threats.

### Contamination by Mycoplasma

Mycoplasma is a genus of bacteria that lacks a cell wall. This makes them resistant to many common antibiotics, such as penicillin, which target cell wall synthesis. Mycoplasma species are the most common contaminants of cell cultures, and they are notoriously difficult to detect. They do not typically cause the culture medium to become turbid, and they do not kill the host cells outright. Instead, they grow slowly in the culture, competing with the cells for nutrients and altering their metabolism.

The mechanism of mycoplasma contamination is insidious. The bacteria attach to the outer surface of the host cell membrane, where they consume amino acids and nucleotides. They also release metabolic byproducts, such as ammonia, which can change the pH of the culture medium. Over time, mycoplasma contamination can alter [gene expression](/blog/guides/gene-expression) in the host cells, change their growth rate, and even induce chromosomal abnormalities. A researcher might notice that their cells are growing more slowly than usual or that their experimental results are becoming inconsistent. These are early signs of mycoplasma contamination, and if they are ignored, the cell line is on a path to cancellation.

Mycoplasma detection is typically performed using a [polymerase chain reaction](/knowledge/molecular-biology/polymerase-chain-reaction) (PCR) assay that targets the 16S rRNA gene, which is highly conserved among mycoplasma species. The assay involves amplifying a specific region of this gene using primers that bind to [conserved sequences](/knowledge/molecular-biology/conserved-sequence). The [PCR reaction](/knowledge/molecular-biology/pcr-reaction) is run for 35 to 40 cycles, and the product is visualized on an agarose gel. A positive result—a visible band at the expected size—indicates contamination. Alternatively, a fluorescence-based assay using a DNA-binding dye such as Hoechst 33258 can be used to visualize mycoplasma in the culture supernatant.

### Cross-Contamination with HeLa Cells

HeLa cells are the ultimate contaminant in cell culture. They are highly proliferative, can survive in suboptimal conditions, and can be inadvertently transferred between cultures through shared reagents, contaminated pipettes, or aerosol droplets. When HeLa cells contaminate another cell line, they often outcompete the original cells, eventually replacing them entirely. The result is a culture that is labeled as one cell type but is actually HeLa cells.

The mechanism of cross-contamination is simple: physical transfer. A researcher might use the same bottle of medium for two different cell lines, or they might use a pipette that has touched a HeLa culture and then touch another culture. The HeLa cells, being robust, survive the transfer and begin to proliferate. Over time, they overtake the original cells. The researcher may not notice any change, because the cells look similar under the microscope. The only way to detect the contamination is through genetic analysis, such as short tandem repeat (STR) profiling, which is discussed later in this article.

The problem of HeLa contamination is so severe that it has its own name: "HeLaization." It is estimated that hundreds of cell lines have been contaminated with HeLa cells over the decades. When a cell line is found to be HeLa-contaminated, it is immediately cancelled. The data generated from that line is considered invalid, because the experiments were actually performed on HeLa cells, not on the intended cell type.

## Evidence for Cancelled Cell Lines

The cancellation of a cell line is not based on anecdote or suspicion. It is based on systematic evidence gathered by researchers and curated by international organizations. The evidence comes in the form of genetic profiles, contamination records, and published case studies.

### The International Cell Line Authentication Committee (ICLAC)

The International Cell Line Authentication Committee (ICLAC) is a body of experts that maintains a registry of misidentified cell lines. The registry is a public database that lists cell lines that have been shown to be contaminated or misidentified. Each entry includes the name of the cell line, the type of contamination (e.g., HeLa, another cell line, or mycoplasma), and the evidence supporting the finding.

ICLAC does not itself perform the testing. Instead, it compiles data from published studies and from submissions by researchers. When a cell line is added to the ICLAC registry, it is effectively cancelled. Journals and funding agencies increasingly require researchers to check the ICLAC registry before starting experiments, and many will not accept manuscripts that use a listed cell line without a clear justification.

### Case Studies of Famous Misidentified Lines

One of the most instructive case studies is that of the "INT-407" cell line, which was originally established from human embryonic intestine. For decades, researchers used INT-407 as a model for intestinal epithelial cells. However, STR profiling revealed that INT-407 is actually a HeLa cell line. The original intestinal cells had been overgrown by HeLa cells at some point in the line's history. The INT-407 line was added to the ICLAC registry and is now considered cancelled.

Another case is the "Chang liver" cell line, which was supposed to be derived from human liver tissue. It was later shown to be a HeLa contaminant as well. The Chang liver line is still used in some laboratories, but it is no longer accepted as a valid liver model. These case studies illustrate a critical point: a cell line's name and history are not sufficient to establish its identity. Only genetic testing can do that.

## Methods Used to Detect Cancellation

Detecting whether a cell line is contaminated or misidentified requires specific laboratory techniques. These methods are the "diagnostic tools" of cell culture, and they are essential for maintaining the integrity of research.

### Short Tandem Repeat (STR) Profiling

Short tandem repeats (STRs) are regions of the genome where a short sequence of nucleotides (typically 2 to 6 base pairs) is repeated multiple times. The number of repeats at each STR locus varies between individuals, making STR profiles a form of genetic fingerprint. In cell culture, STR profiling is used to confirm the identity of a cell line and to detect cross-contamination.

The procedure for STR profiling involves extracting DNA from the cells, amplifying specific STR loci using PCR, and then analyzing the size of the amplified fragments. The PCR reaction uses primers that are fluorescently labeled, allowing the fragments to be detected by capillary electrophoresis. The resulting profile is a series of peaks, each corresponding to a specific allele at a specific locus. This profile is compared to a reference database, such as the one maintained by ATCC, to confirm the cell line's identity.

If a cell line's STR profile does not match the reference profile, the line is misidentified. If the profile shows more than two alleles at a locus (which is unusual for a diploid cell), it may indicate that the culture is a mixture of two different cell lines. STR profiling is the gold standard for cell line authentication, and it is recommended that researchers perform it at least once per year or whenever a new frozen stock is created.

### Mycoplasma Detection Assays

Mycoplasma detection is performed using either PCR or a biochemical assay. The PCR method, as described earlier, targets the 16S rRNA gene. The biochemical method uses an enzyme-linked immunosorbent assay (ELISA) that detects mycoplasma antigens in the culture supernatant. Both methods are sensitive and can detect low levels of contamination.

A newer approach is the use of a luminescence-based assay that detects mycoplasma ATP. The assay is based on the fact that mycoplasma, like all living cells, contain ATP. A reagent that lyses the mycoplasma cells and reacts with ATP to produce light is added to the culture supernatant. The amount of light produced is proportional to the amount of ATP, and therefore to the number of mycoplasma cells. This assay is rapid and can be performed in a microplate reader, making it suitable for routine screening.

## Pros and Cons of Cancelling Cell Lines

The decision to cancel a cell line is not without consequences. There are clear benefits for the scientific community, but there are also drawbacks that must be considered.

### Benefits for Reproducibility

The primary benefit of cancelling a cell line is that it improves the reproducibility of scientific research. When a cell line is cancelled, researchers are forced to find alternatives. This may involve using a well-characterized cell line from a reputable repository, or it may involve deriving a new cell line from primary tissue. In either case, the result is that published data are more likely to be reliable, because the cells used in the experiments are properly identified and free of contamination.

Cancelling a cell line also sends a message to the research community: cell line authentication is not optional. It is a requirement for good science. This cultural shift has already begun, with many journals requiring STR profiling data as a condition for publication.

### Loss of Valuable Research Data

The downside of cancelling a cell line is that it can invalidate years of published research. If a cell line is found to be misidentified, all of the studies that used that line are called into question. This is not to say that the data are necessarily wrong—some of the findings may still be valid, especially if the experiments were well-designed and the conclusions were based on the behavior of the cells rather than their identity. However, the data cannot be interpreted in the context of the intended cell type, and they may need to be re-evaluated.

This loss of data is a real cost, and it is one reason why some researchers are reluctant to cancel cell lines. However, the alternative—continuing to use a contaminated or misidentified line—is worse, because it perpetuates the problem and undermines the integrity of the scientific literature.

## How to Avoid Cancelling Your Cell Culture

Preventing cell line cancellation is a matter of following best practices in cell culture maintenance and authentication. These practices are not difficult, but they require discipline and attention to detail.

### Best Practices for Cell Culture Maintenance

The first line of defense against contamination is proper aseptic technique. This includes working in a laminar flow hood, using sterile reagents, and wearing gloves and a lab coat. It also includes segregating different cell lines to prevent cross-contamination. For example, you should never handle two different cell lines at the same time, and you should use separate bottles of medium for each line.

Another important practice is to test your cultures for mycoplasma on a regular basis. Many laboratories test every new cell line upon receipt and then monthly thereafter. This is a simple PCR or luminescence assay that can be performed in a single day. If a culture tests positive for mycoplasma, it should be discarded immediately, or treated with a mycoplasma removal agent if the cell line is irreplaceable.

### Regular Authentication

Cell line authentication should be performed at regular intervals. The gold standard is STR profiling, which should be done when a new cell line is received, when a frozen stock is created, and at least once a year thereafter. This ensures that the cells in your culture are the cells you think they are.

In addition to STR profiling, you should also maintain a detailed record of your cell lines, including their passage number, the date they were thawed, and any observations about their growth. This record can help you identify problems early, before they become serious.

For those working with [Primary Cell Culture Guidelines](/knowledge/molecular-biology/primary-cell-culture-guidelines), the stakes are even higher, because primary cells have a limited lifespan and cannot be replaced from a repository. Extra care must be taken to ensure that primary cultures are not contaminated, as the loss of a primary culture can set back a project by months.

## Common Pitfalls in Studying Cancel Culture

Even experienced researchers can fall into traps when dealing with cell line issues. Here are some of the most common pitfalls and how to avoid them.

### Ignoring Early Signs of Contamination

The earliest sign of mycoplasma contamination is often a subtle change in cell growth. Cells may grow more slowly, or they may become more sensitive to changes in the medium. These changes are easy to dismiss as "normal variation," but they are often the first indication of a problem. If you notice any change in your cells' behavior, you should test for mycoplasma immediately. Waiting will only make the problem worse.

### Assuming All Cell Lines Are Authentic

It is a common misconception that cell lines obtained from a reputable repository are automatically authentic. While repositories like ATCC and the European Collection of Authenticated Cell Cultures (ECACC) do perform authentication, they cannot guarantee that the line will remain authentic after it has been distributed. Cross-contamination can occur in your own laboratory, and it can occur in the laboratories of other researchers who share cells with you. The only way to be sure is to test.

Another pitfall is assuming that a cell line with a well-known name is the same as the original line. As the case of U87MG demonstrates, the same name can refer to different lines with different origins. Always verify the identity of your cells, regardless of their name or reputation.

### Overlooking the Importance of Passage Number

Every time a cell line is passaged, or subcultured, there is a risk of genetic drift. Over many passages, cells can accumulate mutations that change their behavior. This is not the same as contamination, but it can still make the cells a poor model for the original tissue. To minimize this risk, you should keep passage numbers low and create frozen stocks early in the life of the culture. For more details on this process, see [Cell Passaging](/knowledge/molecular-biology/cell-passaging).

## Summary and Key Takeaways

Cell line cancellation is a serious issue in molecular biology, but it is also a preventable one. By understanding the mechanisms of contamination and misidentification, and by following best practices for cell culture maintenance, you can ensure that your cells remain authentic and your data remain reliable.

- Cell line cancellation occurs when a line is shown to be contaminated or misidentified, making it unsuitable for research.
- Mycoplasma contamination is the most common cause of cell line problems, and it is detected using PCR or luminescence assays.
- HeLa cell cross-contamination is a major issue, and it is detected using STR profiling.
- The ICLAC registry is a key resource for identifying cancelled cell lines.
- Regular authentication and proper aseptic technique are the best ways to prevent cell line cancellation.
- Ignoring early signs of contamination and assuming all cell lines are authentic are common pitfalls.
- Cancelling a cell line improves reproducibility but can invalidate previous research.

## Frequently Asked Questions

### What are some examples of cancel culture in cell culture?

Examples include the INT-407 cell line, which was found to be HeLa cells, and the U87MG line, which was found to be different from the original tumor line. Both were cancelled as valid models for their intended tissues.

### What is the definition of cancel culture in cell culture?

Cancel culture in cell culture refers to the collective decision by the scientific community that a cell line is no longer acceptable for research due to contamination or misidentification. This decision is based on objective genetic and biochemical evidence.

### What are the pros and cons of cancelling a cell line?

The pros are improved reproducibility and reliability of research. The cons are the loss of data from studies that used the cancelled line and the need to find alternative models.

### How can I tell if my cell line is cancelled?

You can check the ICLAC registry, which lists known misidentified cell lines. You can also perform STR profiling to confirm the identity of your cells.

### Why is HeLa cell contamination a problem?

HeLa cells are highly proliferative and can overgrow other cell lines, leading to misidentification. When this happens, experiments are actually performed on HeLa cells, not on the intended cell type, making the results invalid.

### What methods are used to detect [cell line contamination](/knowledge/molecular-biology/cell-line-contamination)?

The main methods are STR profiling for cross-contamination and PCR or luminescence assays for mycoplasma detection.

### Can a cancelled cell line be reinstated?

In rare cases, a cancelled cell line can be reinstated if the original, authentic cells are found and the line is re-established. However, this is uncommon, and most cancelled lines remain cancelled.

## Further Reading

- Machutta K et al. *Defeating Cancel Culture in Surgical Site Infection Research: A Plea to Include Microbial Cultures and Antibiotic Sensitivity Data*. Surgical infections. 2022. [PubMed 36399540](https://doi.org/10.1089/sur.2022.247)
- Lim WK, Iyer NG. *A GD (Gamma-Delta) type of cancel culture*. Immuno-oncology technology. 2024. [PubMed 39717204](https://doi.org/10.1016/j.iotech.2024.100740)
- Mengel M, Mannon RB. *No Time for Cancel Culture: The Importance of Banff Pathology Criteria and Clinical Outcomes*. Journal of the American Society of Nephrology : JASN. 2024. [PubMed 38857893](https://doi.org/10.1681/ASN.0000000000000411)
- Traversa M, Tian Y, Wright SC. *Cancel culture can be collectively validating for groups experiencing harm*. Frontiers in psychology. 2023. [PubMed 37546434](https://doi.org/10.3389/fpsyg.2023.1181872)
- Roldan CJL, Ong AKS, Tomas DQ. *Cancel culture in a developing country: A belief in a just world behavioral analysis among generation Z*. Acta psychologica. 2024. [PubMed 38941914](https://doi.org/10.1016/j.actpsy.2024.104378)
- Zucker KJ. *Introduction to the Special Section "Cancel Culture": Its Impact on Sex/Gender Teaching, Clinical Practice, and Research and a Call for Commentaries*. Archives of sexual behavior. 2023. [PubMed 36607517](https://doi.org/10.1007/s10508-022-02526-x)

## Related Clinical & Scientific Guides

* [MAPK Pathway: Mechanism, Function, and Clinical Relevance](/knowledge/molecular-biology/mapk-pathway)
* [Mammalian Cell Culture Bioreactors: A Practical Guide](/knowledge/molecular-biology/mammalian-cell-culture-bioreactor)
* [Nucleotide Formation: Biosynthesis and Assembly of DNA/RNA Building Blocks](/knowledge/molecular-biology/nucleotide-formation)