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Updated: Jun 15, 2026
A Next-generation Tissue Microarray (ngTMA) Protocol for Biomarker Studies
Published on: September 23, 2014
Tissue microarray constructs to predict a response to chemoradiation in rectal cancer
Sergio Huerta1, John Hrom, Xiaohuan Gao
1Department of Surgery, University of Texas Southwestern Medical Center, United States. Sergio.Huerta@UTSouthwestern.edu
Purpose:
To identify, using tissue microarray (TMA), an immunohistochemical panel predictive of response to ionizing radiation (IR) in rectal cancer.
Methods:
TMA constructs were prepared from archived stage II/III rectal tumors and matching adjacent mucosa (n=38) from patients treated with pre-operative chemoradiation. Immunohistochemistry (IHC) was performed for MIB, Cyclin E, p21, p27, p53, survivin, Bcl-2, and BAX. Immunoreactivity along with clinical variables was subjected to univariate and forward stepwise logistic regression analyses.
Results:
Pathological complete response (pCR) was 23.9%. The number of positive lymph nodes obtained in the resected specimen was associated with pCR. Immunoreactivity for MIB (Sn 15%, Sp 65%, OR 0.33), p53 (Sn 3%, Sp 84%, OR 0.16), Bcl-2 (Sn 11%, Sp 74%, OR 0.35), and BAX (Sn 92%, Sp 80%, OR 46) was associated with pathological response (all p's<0.001). Forward stepwise logistic regression analysis demonstrated that MIB was an independent predictor of a response to chemoradiation (p=0.001).
Conclusions:
A combined panel of mediators of apoptosis alone or combined with clinical factors is a feasible approach that can be applied to rectal tumor biopsies to predict a response to chemoradiation. The most sensitive factor was BAX; while MIB independently predicted a response to chemoradiation.
