Previously missed DNA mutation pattern in colorectal cancer identified

Researchers from the University of California San Diego and collaborators have discovered a previously unrecognized pattern of DNA mutations in colorectal cancer, according to a study published in Nature Communications. This mutation pattern, known as a mutational signature, had been identified in previous cancer-genome data sets but was previously thought to be a combination of other known mutation patterns.

When the researchers examined the pattern more closely, they found it was not associated with the known processes attributed to it. Moreover, the same pattern was detected in three separate colorectal cancer data sets, each comprising over 800 tumors, indicating its significance in some colorectal cancers.

The researchers observed that the mutation pattern emerges relatively late in the development of colorectal tumors. This suggests that there might be a change during tumor development that leads cancer cells to accumulate a new type of DNA damage or copying error. Additionally, tumors exhibiting this newly recognized pattern had more small insertions and deletions in their DNA.

These insertions and deletions can arise during DNA replication and repair, providing further evidence that the newly identified pattern might be linked to these processes.

In essence, this study addresses a critical challenge in cancer genomics: understanding what unusual mutational patterns can reveal about the processes shaping cancer development. The work was conducted by a team called Mutographs, whose mission is to explore the relationship between mutational signatures and cancer development.