Low Level of Microsatellite Instability Correlates with Poor Clinical Prognosis in Stage II Colorectal Cancer Patients

• Main Authors: Ehsan Nazemalhosseini Mojarad, Seyed Mohammad Hossein Kashfi, Hanieh Mirtalebi, Mohammad Yaghoob Taleghani, Pedram Azimzadeh, Sanaz Savabkar, Mohammad Amin Pourhoseingholi, Hasan Jalaeikhoo, Hamid Asadzadeh Aghdaei, Peter J. K. Kuppen, Mohammad Reza Zali
• Format: Article
• Language: English
• Published: Hindawi Limited 2016-01-01
• Series: Journal of Oncology
• Online Access: http://dx.doi.org/10.1155/2016/2196703

The influence of microsatellite instability (MSI) on the prognosis of colorectal cancer (CRC) requires more investigation. We assessed the role of MSI status in survival of individuals diagnosed with primary colorectal cancer. In this retrospective cross-sectional study the MSI status was determined in 158 formalin-fixed paraffin-embedded tumors and their matched normal tissues from patients who underwent curative surgery. Cox proportional hazard modeling was performed to assess the clinical prognostic significance. In this study we found that MSI-H tumors were predominantly located in the colon versus rectum (p=0.03), associated with poorer differentiation (p=0.003) and TNM stage II/III of tumors (p=0.02). In CRC patients with stage II, MSI-L cases showed significantly poorer survival compared with patients who had MSI-H or MSS tumors (p=0.04). This study indicates that MSI-L tumors correlate with poorer clinical outcome in patients with stage II tumors (p=0.04) or in tumors located in the colon (p=0.02). MSI-L characterizes a distinct subgroup of CRC patients who have a poorer outcome. This study suggests that MSI status in CRC, as a clinical prognostic marker, is dependent on other factors, such as tumor stage and location.