Immunohistochemical localization of laminin, collagen type IV and heparan sulfate proteoglycan in human colorectal adenocarcinoma: Correlation with local invasive pattern and lymph node metastasis

The extent of immunohistochemical localization of such basement membrane components (BMs) as laminin (LN), collagen type IV (C-IV) and heparan sulfate proteoglycan (HSPG) were investigated in 78 samples of human colorectal carcinoma, in correlation with histology of the invasive pattern at the parenchymal-stromal border of the invasive margin (PSB) and lymph node metastasis. The immunostaining ratio of BMs at the PSB was significantly lower in the type IV invasive pattern (PSB-IV) than in the other types, and was also significantly related to the incidence of lymphatic invasion and lymph node metastasis. A close relationship was also demonstrated between the PSB-IV and the prognosis of the patient or recurrence of the carcinoma, although there was no statistical significance. Furthermore, the immunostaining ratios of the LN and C-IV in the central areas (CAs) of the carcinoma tissue were also significantly lower in samples with lymph node metastasis than those without metastatic focus. These results thus indicate that the lower degree of immunostaining ratio of BMs at the PSB in human colorectal carcinomas is closely related to both the lymph node metastasis and the patient prognosis, while in addition the varied localization of BMs at the PSB affects diverse histopathological features in the invasive margin of carcinoma tissue. Moreover, the decreased immunostaining deposition of BMs in the CAs of carcinoma tissue also plays an important role in the pathway of lymph node metastasis. Therefore, further attention should be paid to the cellular biology of carcinoma cells localized in the CA, as well as those localized at the PSB, in order to disclose the metastatic cascade of colorectal carcinoma.