Tumor volume of colon carcinoma is related to the invasive pattern but not to the expression of cell adhesion proteins

Tumor volume increases during growth and due to tumor progression various mutations appear that may cause phenotypic changes. The invasive pattern may thus be affected resulting in a more disorganized growth. This phenomenon might be due to mutations in the genome of the adhesion proteins, which are responsible for the structural integrity of epithelial tissue. Tumor volume was assessed in whole mount sections of 33 colon carcinomas using Cavalieri's principle. Images from the entire invasive border were captured and used for calculating the irregularity of the border (Complexity Index). The expression of the adhesion proteins E-cadherin, beta-catenin, Claudin 2 and Occludin was assessed after immunohistochemical staining of two randomly selected areas of the invasive front of the tumor. Statistical significance for differences in volume was obtained for tumor Complexity Index, tumor stage (pT) and lymph node status (pN). Expression of adhesion proteins was significantly perturbed in the tumors compared with normal mucosa but only infrequently correlated to tumor differentiation or invasive pattern. The results show that when tumor volume increases the invasive pattern becomes more irregular which is compatible with tumor progression. A direct contribution of adhesion protein derangement to this process appears to be insignificant.