Sex Bias and Cancer

Differences exist between cancer in males and females on a molecular level.

Researchers in a recent study were able to create a molecular understanding of how gender can affect cancer development.

Data from The Cancer Genome Atlas showed that more than half of the genes studied related to the clinical practice of cancer showed sex-biased signatures in some cancers, according to the study published in Cancer Cell.

"Our study helps elucidate the molecular basis for sex disparities in cancer and lays a critical foundation for the future development of precision cancer medicine that is sex-specific," said lead researcher Han Liang, PhD. "This is a crucial finding as currently, male and female patients with many cancer types often are treated in a similar way without explicitly considering their gender."

Researchers analyzed 30 or more samples for each gender for cancers of the bladder, colon, kidney, brain, rectum, thyroid, liver, lung, and acute myeloid leukemia. They looked for data such as somatic mutations, copy alterations, protein and gene expression, and DNA methylation, according to the study.

Researchers also analyzed molecular differences between male and female patients, which showed 2 sex-effect groups associated with distinct incidence and mortality profiles that comprise 53% of clinically actionable genes, according to the study. These genes are either therapeutic targets or biomarkers, which can help estimate patient survival or tumor response.

Researchers found that the weak group contained only a small amount of sex-affected genes, while the strong group had a larger number of sex-biased molecular signatures. These findings suggest that equal treatment for both genders in the weak group may be appropriate, but observations made in the strong group are statistically significant, the researchers wrote.

"Special consideration should be given to those in the strong sex-effect group in terms of both drug development and practice," Dr Liang said. "For a therapeutic target with a strong sex-biased signature, sex-specific clinical trials may be more likely to succeed. This new information is vital as the fundamental issue of sex differences for cancer prevention and therapy has not been investigated systematically."

Researchers also noted another potential discovery in regard to sex bias.

"Interestingly, our analysis also suggested that sex bias might be amplified during the tumor formation process," concluded Dr Liang. "However this observation should be interpreted with caution at this early stage as further efforts are needed to determine the relative contributions of other factors, including tumorigenesis, sex chromosomes and hormones."