Salivary-type amylase producing lung cancers examined clinically and pathologically in 260 Japanese patients of lung lobectomy or segmentectomy

Abstract

The causative mechanisms of lung cancers producing salivary-type amylase (S-Amy) were hypothesized from clinical and pathological analysis of lung cancers. A total of 260 Japanese patients who received lung lobectomy or segmentectomy during the last 4 years at Hamamatsu University Hospital, Japan, were objective patients in this study. Among the 260 patients, 212 patients were operated on for lung cancers. Of the 212 patients, 132 (62%) had adenocarcinoma and 38 (18%) had squamous cell carcinoma (SCC), of which 32 adenocarcinoma, and 8 SCC patients had metastatic lung cancers. Twenty-five (78%) of the 32 adenocarcinoma patients showed metastatic cancers from colon cancers to the lungs, especially from rectal and sigmoid colon cancers. Twenty-one (21%) of 100 primary adenocarcinoma patients and 8 (27%) of 30 primary SCC patients had double cancers coexisting with the lung cancers during the last 7 years. Among the 29 patients of double cancers, 4 lung cancer patients showed coexisting gastric cancers. The mortality rate of 79 adenocarcinoma and 22 SCC patients with primary lung cancer but not double cancer was 14% during the 4 years of this study. In 12 (12%) patients of the 101 patients with primary lung cancers, bone metastases were confirmed by bone scintigraphy. All the nine (9%) patients with brain metastases were adenocarcinoma, which was confirmed by brain magnetic resonance imaging (MRI). Serum amylase levels of the 79 adenocarcinoma and 22 SCC patients were 232 ± 343 (SD) and 156 ± 161 (SD) (IU/l), respectively, 1 day post-operation. Diabetes mellitus (DM) or borderline DM were found in 34 (43%) of the 79 adenocarcinoma and 16 (73%) of the 22 SCC patients. Of the 14 patients who died of lung cancers, 11 (79%) had DM. From these clinical and pathological findings, more than 70% of Japanese lung cancers were hypothesized to have developed from the oncogene of a retrovirus inserted into the 5' promoter of S-Amy genes (AMY1) in 60–70 age groups.