Tiam1 Protein Expression in Primary and Metastatic Colorectal Carcinoma: A Retrospective Study of 200 Cases

Objective : T-cell Lymphoma Invasion and Metastasis 1 (Tiam1)protein is a guanine nucleotide exchange factor that activates proteins of the Rho family of GTPases, specifically Rac1. Expression of Tiam1 protein has been reported in various human cancers and has been associated with lymphangiogenesis and promotion of tumor metastasis. The objective of this study was to further evaluate the expression of Tiam1 in primary and metastatic colorectal cancer (CRC) and its association withvariousclinicopathological parameters, includinggender, age, tumor size, Dukes stage, tumor grade, lymph node status and original location of the primary tumor (colon versus rectum). Methods : The expression of Tiam1 was detected by immunohistochemistry in 200 samples of primary CRC tissues and in 100 samples of lymph node tissue with CRC metastases. Results : Tiam1 was overexpressed in the majority of both primary (69,5% of the cases) and metastatic (63% of the cases) CRC tumor tissues. Overexpression of Tiam1 in primary CRC was statistically associated withlowertumor grade(P=0,04), whereas in metastatic CRC a statistically significant association between Tiam1 expression and  female gender (P=0,003), tumor size >5cm (P=0,001) and localization  of the primary tumor in the colon (P=0,009) was found. Conclusion : Overexpression of Tiam1 protein may represent a frequent event in CRC. Additional studies are warranted to further investigate its potential value as a marker of prognosis and treatment response in this form of cancer.