Expression of integrin genes and proteins in progression and dissemination of colorectal adenocarcinoma

BACKGROUND This study aimed to evaluate the relationship between the expression levels of selected integrin genes and proteins and cell differentiation, TNM stage, histological type and other variables potentially associated with the progression and dissemination of colorectal carcinoma (CRC). METHODS A total of 114 patients (63 men and 51 women) were treated for CRC between 2006 and 2009, including 25 (21.9%) TNM I, 39 (34.2%) TNM II, 34 (29.8%) TNM III, and 16 (14.1%) TNM IV. Regarding grade, 91 (79.8%) were grade II, 14 (12.2%) were grade III and nine (7.8%) were grade I. Reverse-transcription polymerase chain reaction (RT-PCR) and tissue microarray (TMA) methods were used to examine the expression levels of the genes ITGAV, ITGA3, ITGA5, ITGB5, and ITGA6, and their proteins, respectively. RESULTS In relation to TNM staging, ITGB5 and ITGA3 were over-expressed in stages III versus I. These results were confirmed by TMA analysis. In terms of age, ITGA5 was under-expressed according to RT-PCR, but over-expressed by TMA in patients over 60 years, while ITGA5 gene and protein levels were increased in mucinous carcinomas. In addition ITGAV gene and protein levels were elevated in tumors with neural invasion, and ITGA6 gene and protein were over-expressed in cases with venous invasion. All these results were significant at P < 0.05. CONCLUSION The results of this study suggest that over-expression of some integrins is associated with TNM III stage, increased risk of vascular and neural invasion, and mucinous histology in patients with CRC.