Abstract
This study was designed to assess the mechanism of obstruction in obstructing colorectal carcinomas. Thirty-five cases of obstructing colorectal carcinoma and 34 cases of non-obstructing carcinoma were studied. The lesions were immunohistochemically analyzed using antibodies for pan-cytokeratin, α-smooth muscle actin, matrix metalloproteinase-7, 47-kDa heat shock protein (Hsp47), basic fibroblast growth factor (bFGF), myeloperoxidase, and CD68. Compared with non-obstructing cases, obstructing carcinoma cases included lesions of poorer differentiation. A higher value of tumor budding was observed in obstructing than in non-obstructing carcinoma. A higher number of α-smooth muscle actin-positive myofibroblasts, a higher expression of Hsp47 in stromal spindle cells, and a higher expression of bFGF in inflammatory cells were also significant in obstructing carcinoma. Therefore, obstructing colon carcinomas were characterized by poorer differentiation of cancer cells, a high level of tumor budding, and stromal myofibroblast proliferation resulting in fibrosis. Correlative Hsp47 expression in fibroblasts with bFGF in inflammatory cells may contribute to stromal fibrosis.