Shimagaki et al. reported that genetic analysis using FoundationOne companion diagnostics identified 11 somatic mutations, including those in TP53 and STK11, in UESL.2) Loss of function due to TP53 mutations has been reported in other UESL gene analyses, indicating that p53 may be a useful therapeutic target in the future.9,10) In the present case, immunostaining showed that both the UESL and adenocarcinoma components were p53-positive. The gene discussed is STK11; the disease is adenocarcinoma.