Zhang X, et al. - Using data from the U.S. Cancer Statistics registry, researchers ascertained if the underlying reasons for variations in hepatocellular carcinoma (HCC) among subgroups of the population by age, gender, race/ethnicity, and birth cohort are uniform or if they interact with each other or have changed over time. Between 2001 and 2015, men and women ≥ 50 years showed an increase in HCC rates, women aged 40-49 had stable HCC rates, but males aged 40-44 and 45-49 had a decrease in HCC rates. This resulted in a decrease in the male-to-female incidence rate ratio (IRR) among persons aged < 50 from 4.63 in 2001 to 2.42 in 2015, however, the ratio remained stable over time among persons aged ≥ 50. Successive cohorts of males born after circa 1956 had lower HCC rates, on the other hand, females born circa 1991 had higher HCC rates than those among females born circa 1956. Such outcomes indicate that the epidemiology of HCC is changing from a disease with striking male predominance to one with less male predominance.