Whole-exome sequencing in a patient with synchronous triple primary malignancies involving lung cancer: a case report

The incidence of multiple primary malignancies (MPMs) has been increasing rapidly in recent years, however, the genetic pathogenesis is largely unknown on account of rare cases, especially for those patients who are diagnosed with three or more tumors. Under these circumstances, whole-exome sequencing (WES) may help to provide more comprehensive genomic information and guidance to proper therapeutic strategies. Here, we presented a rare case of a 66-year-old Chinese male patient who was diagnosed with synchronous triple primary malignancies: esophageal squamous cell carcinoma (ESCC), lung adenocarcinoma (LA), and hepatocellular carcinoma (HCC). Tumors were surgically removed within 3 months. WES was performed when the patient suffered from cancer recurrence and tumor-specific neoantigens were predicted. Each tumor displayed a distinct somatic mutation profile, providing direct evidence of independent origins. No shared driver gene mutation or neoantigen was detected among the three tumors. Two germline alterations of cancer susceptibility genes-SPINK1 c.194 + 2T>C and JAK3 c.425G>A were identified. This case is the first report of synchronous primary triple cancers covering the esophagus, lung, and liver. Our findings highlight the complexities of MPMs that even when under identical germline genetic backgrounds, the occurrence of MPMs can be a random event and driven by distinct somatic gene mutations. Synchronous multiple primary cancers that originated from different organs may not have common therapeutic gene targets, and it can be difficult to find a treatment to cover all the tumors.