The usefulness of immunohistochemistry in sporadic colorectal cancer

Colorectal cancer is an important disease with a large morbidity and mortality and also with increasing health care costs because of widespread of the multi-modal therapy and of the new drugs that continue to appear. There are 678.000 colorectal cancer cases and 400.000 deaths from the disease worldwide. It is the second commonest cause of cancer death in the European Union but, unlike the commonest cause of cancer related death that is lung cancer, the basis of the disease initiation is currently not understood. At the same time, the incidence increases with age, the carcinomas being rare before the age of 40 years, excepting individuals with genetic predisposition or predisposing conditions such as inflammatory bowel diseases. The early detection of colorectal cancer is potential associated with an important decrease of the cancer related mortality.

Our study proposes to find out the significance of some immunohistochemical markers (VEGF, p53, CK20 and CEA) in sporadic colorectal carcinoma cases and to establish the statistical correlations between molecular markers and tumor grade and stage.

We investigated histopathological 40 inpatients (19 female and 21 males) who undergone surgery for colorectal carcinomas in "Sf. Ioan" Emergency Hospital, Bucharest, between September 2005-September 2006. We proceeded the histopathological examination to establish the grade, stage and the main features of the tumors, and then we analyzed using ABC method for immunohistochemistry the following markers for 20 selected cases: vascular endothelial growth factor (VEGF), carcinoembrionic antigen (CEA), cytokeratin 20 (CK20), and p53 oncoprotein. Finally, we analyzed statistical the results using t-Student test.

The distribution of colorectal cancer cases (n = 40) regarding the age has showed the preponderance of patients older than 70 years (22/55%) and a small percentage of younger adults (2/5%). The repartition of colorectal tumors of sex ratio outlines a small difference between males (21/52.5%), and females (19/47.5%). The histopathological analysis of tumor grade in the 40 cases has revealed a high percent of moderate grade tumors (23/57.5%), in comparison with the poor differentiated tumors (11/27.5%) and the well-differentiated cancers (6/15%). The neovascularity within the stroma, the main features of tumor growth, has been noticed in 15 cases (3.75%), and also an important inflammatory lymphocyte infiltrate in nine cases (22.5%). We have noticed positive correlation between VEGF1 and CK20 (r = 0.4, p = 0.05), and between VEGF1 and CEA (r = 0.88, p = 0.001). In addition, our results demonstrate a positive correlation between tumor grade and CEA (r = 0.43, p = 0.009), and no relation among the other markers.

Our present study shows that CK20 and CEA are positive immunostaining markers no matter the stage (100%). The oncoprotein p53 has been negative in T1 and T2 stages, but in advanced stages has been positive in a half of cases (50%). Regarding the location, p53 and VEGF showed positively results whatever the topography. We have noticed a direct proportional relation in VEGF expression and CEA, and CEA and tumor grade (r = 0.88, p<0.001).