*3.4. Investigation of the Discrepancies between the Clinical and*/*or Histopathological Diagnoses and Genetic Diagnosis*

Table 1 shows the discrepancies between and among the clinical, pathological and genetic diagnoses of the primary or metastatic lesions in all 37 patients. The clinical diagnoses were comprehensively determined, mainly on the basis of imaging findings and clinical course by the cancer board of the hospital (comprised of thoracic surgeons, pulmonologists, pathologists and radiologists). The pathological diagnoses were determined on the basis of the postoperative pathological findings, especially the differences in the tissue morphology and cellular atypia detected by pathologists. The genetic diagnoses were determined on the basis of digital and statistical analyses of overlaps in the mutation profiles of individual tumors. Discrepancies between the genetic diagnosis and clinical and/or histopathological diagnoses were observed in 11 patients (29.7%). In the patients with synchronous tumors, primary and metastatic tumors were eventually diagnosed on the basis of genetic diagnosis in 24 and 2 patients, respectively. In the 11 patients with metachronous tumors, primary and metastatic

tumors were diagnosed in 5 and 6 patients, respectively, in the same manner. The distribution of primary and metastatic tumors between synchronous and metachronous tumors was significantly different; thus synchronous multiple lung tumors were deemed likely to be primary lesions.


**Table 1.** Mutation analysis of the multiple lung cancers.

The cases in which the diagnoses were inconsistent in the clinicopathological and genetic examinations are indicated by \*.
