How to efficiently suspect a germline gene variant(presumed germline pathogenic variant: PGPV)in comprehensive tumor-profiling tests using only cancer tissue(cells)as a sample is an important issue. This is because a few percent are derived from germline variants, which leads to the diagnosis of hereditary tumor syndromes and is useful information for the health management of patients and relatives. Clues include allele frequency, gene type, germline founder mutation, age of onset, present illness and past history, cancer type, family history, and tumor cell proportion. More than 97% of patients want to know such secondary findings before the test, but only about 23% of patients undergo confirmation tests even if PGPV is detected, and it is necessary to improve this in the future.