New research by scientists at Stanford University School of Medicine and 23andMe sheds more light on the genetics of melanoma, the deadliest form of skin cancer.
Published today in the journal Oncotarget, this genome wide association study quickly replicated 21 genetic variants associated with melanoma that were identified from seven other studies. In addition to replicating those variants, the study found one novel variant near a gene region known as BASP1 which could be protective against melanoma. The researchers found that in individuals with this form of cancer, the expression of BASP1 was suppressed, conferring an almost two-fold increased risk.
“This implicates a potential tumor-suppressive role for BASP1 in melanoma,” the researchers said.
Taken together the findings confirm an association between melanoma and genes involved with pigmentation, tumor suppression, the maintenance of telomere length, the formation of moles, as well as DNA repair.
Skin cancer is the most common form of cancer. There are three main types — basal cell carcinoma, squamous cell carcinoma, and melanoma. Basal cell carcinoma is the most common of the three and affects more than four million people annually in the United States. It is rarely life threatening. Squamous cell carcinoma affects more than one million people. While melanoma is the rarest of the three — accounting for only about one percent of all skin cancers — it leads to the majority of skin cancer deaths each year.
This research on melanoma follows fast on the heels of two other skin cancer studies completed last year by the same group of scientists, one of which was the largest–to-date on the most common form of skin cancer, basal cell carcinoma. All of these studies used data contributed by 23andMe customers who consented to participate in research.
In that study researchers identified 31 genetic variants associated with that form of skin cancer. Fourteen of those variants were new associations. The scientists also conducted a study that looked at cutaneous squamous cell cancer, which was one of the first genome-wide association studies ever done on that form of skin cancer. They found 11 genetic variants associated with cutaneous squamous cell cancer — four of those have never been seen before.
In each of these studies the researchers used a similar two-stage process, one for discovery and the other to confirm the findings. The scientists first conducted a large genome-wide association study using data from 23andMe customers who consented to participate in research. This included both individuals who reported having the type of cancer being studied, as well as others without the condition who were used as controls. In the second state, a confirmatory genome-wide association study was performed using data from another source.
In the case of the study on melanoma, the researchers used more than 290,000 23andMe customers who consented to research. More than 4,800 of those reported that they’d been diagnosed with melanoma. In the second stage of the study, the confirmatory stage, the researchers used data from a group of more than 2,000 patients involved in a study done by MD Anderson Cancer Center, more than half had melanoma.
Beyond the findings from this study on melanoma, the researchers singled out the power of 23andMe’s research model.
“This two-stage (genome wide association study) validates the use of consumer self-reported data as a platform for discovery of new cancer-related genes,” the researchers said.