OBJECTIVE
To study the expression, clinicopathologic correlation and prognostic significance of caveolin-1 in lung adenocarcinomas(LAC).
METHODS
Immunohistochemical study (EnVision method) for caveolin-1 and TTF-1 was carried out in 185 cases of LAC encountered during the period from 2005 to 2010. The correlation between caveolin-1 expression and various clinicopathologic parameters was analyzed statistically.
RESULTS
The rate of caveolin-1 expression in the 185 cases of LAC was 26.5% (49/185) and significantly lower than that in normal lung tissue (P<0.01). There was also higher rate of caveolin-1 expression in male patients (P=0.004), smokers (P=0.006), tumors larger than 3.5 cm (P=0.048), predominantly solid tumor subtype (P=0.025), high tumor grade (P=0.044), tumors with vascular invasion (P=0.019), lymph node metastasis (P=0.030), recurrence (P=0.021) and high clinical stage (P=0.027). The expression level of caveolin-1 in TTF1-negative cases was significantly higher than that in TTF1-positive cases and caveolin-1 expression also negatively correlated with TTF-1 expression in LAC (r=-0.154, P=0.037). The five-year overall survival rate of patients with caveolin-1 positive tumors was lower than that in caveolin-1 negative group (P<0.01).Univariate analysis indicated the expression level of caveolin-1 and TTF-1 (P<0.01), histologic subtype (P=0.002), tumor grade (P=0.002), tumor size (P=0.009), vascular invasion (P=0.019), lymph node metastasis (P=0.018), recurrence (P=0.032) and clinical stage (P=0.024) correlated with the survival of patients with LAC. COX multivariate analysis revealed that LAC with caveolin-1 positive expression, TTF-1 negative expression and high tumor grade carried a significantly unfavorable prognosis.
CONCLUSION
Caveolin-1 expression correlates with histologic subtype, tumor grade, invasiveness and metastatic potential of LAC. The detection of caveolin-1 in LAC is helpful in predicting prognosis.LAC with caveolin-1 expression carries a poor prognosis.