Jiali Han, Ph.D., and colleagues of Indiana University discovered eight new loci—locations on a person’s genome—that are susceptible to the development of squamous cell skin cancer.
Researchers previously identified 14 loci with increased risk for squamous cell skin cancer. A new study confirmed those findings while adding eight new genomic locations, bringing the total identified risk loci to 22.
Han and colleagues analyzed six international cohorts totaling approximately 20,000 squamous cell skin cancer cases and 680,000 controls. More than one-third of the genomic data came from genetic testing company 23andMe research participants. Additional datasets came from the Nurse’s Health Study, Health Professionals Follow-up Study, the Icelandic Cancer Registry and the Ohio State University Division of Human Genetics sample bank.
“This is the largest genetic-associated study for squamous cell carcinoma of the skin,” says Han. “Our multidisciplinary research sheds light on new biology and the etiology of squamous cell carcinoma, confirming some important genes and also identifying genes involved in this particular cancer development.”
Research findings confirmed that pigmentation genes can also be a person’s skin cancer susceptibility gene, but they also identified additional molecular pathways. Physical genomic traits such as fair skin, freckles, blue eyes and brown hair were associated with the risk loci. Researchers have long known that fair skin and sun exposure are risk factors for squamous cell skin cancer.
“We can certainly say there is some genetic overlap between squamous cell carcinoma, basal cell carcinoma and melanoma—the three major types of skin cancer—but we also found some genes are specific for squamous cell carcinoma,” Han continued.
Squamous cell and basal cell are also known as non-melanoma skin cancers. Both usually respond to treatment and rarely spread to other parts of the body, according to the National Cancer Institute. Melanoma is more aggressive and can spread to other parts of the body if not diagnosed early.
Han and collaborators are continuing to build the population sample to identify more risk loci, even with the 22 genomic regions identified. The study found only 8.5% of the heritable risk for squamous cell skin cancer.