What Is the Cancer Gene Census & Why Is It Important?

The Cancer Gene Census, or CGC, is an authoritative catalog of genes with a well-documented causal role in cancer. Maintained by experts at the Wellcome Sanger Institute, it functions as a standardized resource for the global scientific and medical communities. The primary purpose is to consolidate vast amounts of research into a single list, distinguishing genes with solid evidence of driving cancer from others that might be mutated by chance.

This resource systematically evaluates evidence from scientific publications to ensure every included gene has a proven connection to the disease, which helps standardize cancer genetics research worldwide. The census is part of the larger Catalogue of Somatic Mutations in Cancer (COSMIC) project, which documents mutations found across all forms of human cancer.

Criteria for Gene Inclusion

For a gene to be included in the Cancer Gene Census, it must have substantial, published evidence demonstrating its role in driving cancer. The curation team at the Wellcome Sanger Institute requires clear mutation patterns in specific cancer types, verified by at least two independent research studies. This literature-based approach ensures the census remains a trusted list by excluding data from purely statistical interpretations that lack functional validation. The focus is on identifying “driver” genes, which are genes that, when altered, confer a growth advantage to cells.

The census classifies genes into two main categories based on evidence. Tier 1 is for genes with the most robust proof of a causal role in cancer, supported by functional studies and clear patterns of mutation in tumors. These genes have a documented impact on the biological “hallmarks” of cancer, such as sustained cell proliferation or the evasion of cell death.

Tier 2 includes genes with strong indications of a role in cancer, but for which the evidence is not as comprehensive as for Tier 1 genes. These genes often come from more recent studies and require more data to fully confirm their function. This two-tiered system allows the census to be a definitive list while also acknowledging promising, developing research.

Information Within the Census

The Cancer Gene Census is a rich database offering detailed information for each entry. Every gene is accompanied by a description of its normal cellular function, providing a baseline for understanding how its alteration contributes to disease. This context helps researchers and clinicians understand the specific mechanisms involved in cancer.

For each gene, the census details its specific role in cancer, classifying it as an oncogene (actively promotes cancer when mutated) or a tumor suppressor gene (contributes to the disease when inactivated). It also describes the types of mutations observed, including point mutations, deletions, gene fusions, or changes in copy number.

The database catalogs the specific tumor types in which these mutations are commonly found. Many genes are known to drive cancer in multiple, distinct tissues, and the census captures this complexity. For many genes, particularly those in Tier 1, the census also provides a summary of their function in relation to the established hallmarks of cancer.

Clinical and Research Applications

In a clinical setting, the Cancer Gene Census helps interpret genomic sequencing results from a patient’s tumor. Sequencing can reveal thousands of mutations, and the census helps oncologists distinguish the “driver” mutations fueling the cancer from random “passenger” mutations. This distinction is foundational to personalized medicine, allowing treatments to be tailored to the cancer’s genetic makeup.

For example, if a lung cancer patient’s tumor has a mutation in the EGFR gene, a clinician can use the census to confirm it is a known driver in that cancer type. The census shows that specific EGFR mutations act as oncogenes, promoting tumor growth. This knowledge guides treatment, as targeted drugs like osimertinib are designed to inhibit the mutated EGFR protein, often improving outcomes compared to chemotherapy.

For cancer researchers, the census is a resource that accelerates the pace of discovery. It provides a validated list of genes to prioritize for further study, helping scientists focus their efforts on targets with a confirmed role in the disease. By analyzing the genes in the census, researchers can identify biological pathways commonly disrupted across various cancer types.

This curated list of genes is also a starting point for the development of new drugs. Pharmaceutical companies and academic researchers use the census to identify and validate new targets for the next generation of targeted therapies. By understanding which genes drive different cancers, scientists can design molecules aimed at inhibiting those specific drivers.