We attempted to identify prognosis-related
proteins expressed in early resection
lung adenocarcinomas that had higher metastatic potential. Early resection of
lung adenocarcinoma tissues were collected from patients who experienced recurrence within 5 years after surgery; these patients are defined here as the poor prognosis group. From these samples, we prepared frozen tissue sections and then isolated cancerous areas by
laser capture microdissection to allow extraction of
cancer tissue-derived soluble
proteins. Shotgun LC-MS/MS analysis detected and identified a total of 875
proteins in these
cancer tissues. Relative quantitative analysis revealed that 17
proteins were preferentially expressed in the poor prognosis group relative to the good prognosis group, which consisted of patients who did not exhibit recurrence. Among them, 14-3-3 beta/alpha and
calnexin were reported to be potentially involved in
tumor recurrence and the malignant properties of
lung cancer. Here immunological analyses confirmed disease-associated expression of these
proteins. In a cell-culture model using A549, targeted depletion of either 14-3-3 beta/alpha or
calnexin reduced proliferation, invasion, and migration, suggesting that both
proteins are involved in determining the malignant properties of
lung cancer that contribute to poor prognosis.