 You are a biomedical researcher, and please answer the following question based on the context. 
In your answer, please first state the final answer in YES/NO/MAYBE, then include a brief explanation.

### Question: Can a biomarker-based scoring system predict pathologic complete response after preoperative chemoradiotherapy for rectal cancer?

### Context: 1: Numerous molecular markers have been investigated as potential predictors of tumor responses to preoperative chemoradiotherapy (preCRT) for rectal cancer.
2: To develop a system in which biomarkers are used to predict the likelihood of a pathologic complete response (pCR) to preCRT.DESIGN &
3: This is a retrospective analysis of tumor specimens collected prior to preCRT from 81 patients who underwent curative resection for primary rectal adenocarcinoma between June 2008 and February 2012.
4: Using tissue microarrays and immunohistochemistry, expression levels of twelve candidate biomarkers (p53, p21, Bcl2, Bax, EGFR, Cox-2, MLH-1, MSH-2, Ku70, VEGF, TS, Ki-67) were evaluated in paraffin-embedded tumor samples collected before preCRT. The correlation between biomarker expression levels and the pathologic response to preCRT was assessed based on histopathological staging (pTNM) and tumor regression grade (TRG).
5: Expression levels of 4 biomarkers (p53, VEGF, p21, Ki67) correlated with pCR. Patients showing low expression of p53 and/or high expression of VEGF, p21, and Ki67 exhibited a significantly greater pCR rate. A scoring system devised so that one point was given for each biomarker whose expression level correlated with pCR (score range: 0-4) showed that 1 of 26 patients with scores of 0 to 1 achieved pCR, whereas 26 of 55 patients with scores of 2 to 4 achieved pCR (3.8% vs. 47.3%, p<0.001). For prediction of pCR, the scoring system showed 96.3% sensitivity, 46.3% specificity, a 47.3% positive predictive value, and a 96.2% negative predictive value.
6: Immunohistochemistry has limitations related to reproducibility and the ability to provide quantitative information. In addition, this study lacks test and validation sets.


###Response: Expression levels of 4 biomarkers correlated with pCR after preCRT for rectal cancer. A scoring system based on levels of biomarker expression showed good sensitivity and negative predictive value for pCR.
 