Genomic characterization of hepatoid tumors: context matters.

Hepatoid tumors (HT) are rare neoplasms, morphologically resembling hepatocellular carcinoma, which arise in several organs other than the liver. A comprehensive molecular profile of this group of neoplasms is still lacking. Genomic characterization of 19 HT from different organs (3 colon, 4 esophagogastric, 4 biliary, 6 genitourinary, 2 lung) was performed using a multigene next-generation sequencing panel. NGS unraveled a composite molecular profile of HT. Their genetic alterations were clearly clustered by tumor site: i) colorectal HT displayed microsatellite instability, high tumor mutational burden, mutations in ARID1A/B genes and NCOA4-RET gene fusion (2/3 cases); ii) gastric HT had TP53 mutations (2/4); iii) biliary HT displayed loss of CDKN2A (3/4) and loss of chromosome 18 (2/4); iv) genital HT showed gain of chromosome 12 (3/6); v) lung HT had STK11 somatic mutations (2/2). The only commonly mutated gene occurring in HT of different sites was TP53 (8/19 cases: 2 colon, 2 esophagogastric, 2 biliary, 1 genital, 1 lung). This study shows that most genetic alterations of HT were clustered by site, indicating that context matters. The novel potential targets for HT precision oncology are also clustered based on the anatomic origin. This study shed light into the biology of these rare cancers, and may have important consequences for treatment decision and clinical trial selection for HT patients.