Abstract: Objective To find out the distribution of extracellular matrix (ECM) in squamous cell carcinoma (SSC) and explore its biological significance. Methods Fifty cases of SSC were studied by immunohistochemistry with antibodies to laminin (LN), fibronectin (FN), PCNA, and p53. Results Three types of distribution patterns were found. i.e., discontinuous peri carcinoma nest type, fragmentary type, and vascular stroma type. The three types were correlated closely with the growth, differentiation and proliferation of tumor. Basement membrane was present in 3 cases with large invasive tumor nests, shown by continuous linear distribution of FN and LN. Conclusion The expressions of FN and LN decrease markedly, but the absence of basement membrane does not necessarily define invasive SSC, and the correlation of the presence of basement membrane and histologic pattern of invasive tumor suggests that SSC is capable of undergoing focal differentiation before invasion and metastasis have occurred. The distribution of FN and LN might represent the malignant degree of SSC.

Key words: Carcinoma, squamous cell, Fibronectins, Laminin