Staining pattern of type IV collagen and prognosis in early stage adenocarcinoma of the lung.

AIMS To examine the prognostic value of basement membrane expression in early stage adenocarcinoma of the lung. METHODS Using antibodies to type IV collagen, basement membrane expression at the tumour-stromal border was immunohistochemically analysed in 30 patients with early stage adenocarcinoma of the lung (pstage I and pstage II). Two patterns of staining for type IV collagen were observed: in the first one the staining line was conserved or partially fragmented; in the second the staining line was widely fragmented or absent in more than 10% of the tumour area. The first staining pattern was categorised as continuous and the second as discontinuous. RESULTS Of the 24 patients with pstage I adenocarcinoma, 12 (50%) cases showed a continuous pattern. In only one (16.7%) of the six patients with pstage II adenocarcinoma was this pattern evident. Five year survival was greater in pstage I adenocarcinoma (65%) than in pstage II adenocarcinoma (17%), but the difference was not significant. When the analysis was restricted to the 24 patients with pstage I adenocarcinoma, five year survival was better in continuous pattern cases (88%) than in discontinuous pattern cases (20.5%) (p < 0.05). The survival curve of 12 patients with pstage I adenocarcinoma and a discontinuous pattern resembled that of the six patients with pstage II adenocarcinoma. CONCLUSION These findings suggest that patients with pstage I adenocarcinoma and a discontinuous pattern have histopathologically unrecognised micrometastasis when they come to surgery. The staining pattern of type IV collagen could help in the prognosis of pstage I adenocarcinoma of the lung after surgery.