Introduction:
Cavin 2 down-regulation is reported in several malignant tumors and is associated with tumor progression. However, the role of Cavin 2 in lung adenocarcinoma is unknown. This study aimed to investigate the prognostic and diagnostic significance of Cavin 2 in lung adenocarcinoma.

Material and methods:
Cavin 2 expression levels were examined in 150 cases of lung adenocarcinoma and matched adjacent normal lung tissues using RNA extraction and reverse transcription-quantitative polymerase chain reaction (RT-qPCR), Western blotting and immunohistochemistry (IHC) assays. Then, the relationship of Cavin 2 expression with clinicopathological characteristics and patients’ survival was further evaluated in lung adenocarcinoma.

Results:
QPCR and Western blotting analysis indicated that Cavin 2 expression levels were significantly lower in lung adenocarcinoma tissues compared with those in adjacent normal lung tissues (p < 0.0001). The IHC results showed that positive expression of Cavin 2 was mainly located in cytoplasm as brown, but was hard to detect in lung adenocarcinoma tissues. The low-expression rates of Cavin 2 in lung adenocarcinoma and adjacent normal lung tissues were 62.0% and 20.0%, respectively, and the difference was significant (p < 0.0001). Lower expression of Cavin 2 was significantly associated with tumor size, TNM stage and lymph node metastasis (p < 0.05).

Conclusions:
Cavin 2 has low expression in lung adenocarcinoma, which might be regarded as a potential prognostic and diagnostic biomarker.