Sonic hedgehog pathway expression in non-small cell lung cancer

Objective: Activation of the hedgehog pathway is an important signaling mechanism crucial in embryogenesis and has strong links to carcinogenesis. This study investigates the expression of the Sonic hedgehog pathway molecules in non-small cell lung tumors as it relates to clinical outcome of various non-small cell lung cancers. Methods: A tissue microarray with 81 samples from 42 patients with various non-small cell lung cancer histologies was examined without the aid of laser microdissection. All samples were stained with antibodies directed against Sonic hedgehog, Ptch-1, Smoothened, and Gli-1. Results: Most of the tumor samples showed negative to weak expression of the pathway proteins (Sonic hedgehog, 38% negative to 20% weak; Ptch-1, 100% negative; Smoothened, 69% negative to 7% weak; Gli-1, 57% negative to 5% weak) compared with higher expression in normal lung epithelial cells. Conclusion: The same pathway expression did not correlate with clinical outcome. While our results do not provide any indication that the pathway molecules are correlated to overall patient survival possibly due to the limited sample size, our study shows minimum overexpression of Sonic hedgehog pathway in non-small cell lung cancer and this did not correlate clinically with patient outcome.