Molecular characteristics of hepatocellular carcinomas from different age groups

While most patients in Western countries who are diagnosed with HCC are in their 50s and 60s, HCCs diagnosed at extremes of the age spectrum (i.e., < 40 years and ≥ 75 years) are less common and have been linked with distinct geographic locations and etiologies. Using multiplatform profiling, we identified differences in genetic alterations and protein expression in different age groups within a large cohort of HCC patients (N = 421). Young adult HCC patients (18-39 years' old) were more likely to be female, living in the West and Midwestern United States, and showed decreased androgen receptor, drug resistance and pro-angiogenic protein expression compared to older patients. TP53 mutations were the most frequent alteration in young adults (19%), whereas CTNNB1 mutations occurred in 30-33% of patients ≥ 40 years' old. The overall frequency of pathogenic and presumed pathogenic mutations was observed to increase significantly with advancing age. To our knowledge, these data represent one of the only studies to analyze age-specific molecular profiles in HCC, and provide a basis for further exploration and validation of these findings with respect to their clinical and therapeutic implications.