Colorectal cancers are the third most common in both sexes and they are the K02288 second most common cause of cancer-related death. mucinous differentiation pathological tumor stage lymphovascular and perineural invasion lymphocyte amount in the tumor microenvironment surgical border and lymph node metastasis. We prepared multiple tissue blocks which had 4-millimeter tumor. Immunohistochemically MLH-1 MSH-2 PMS-2 MSH-6 primary antibodies were studied. Statistically “Kruskal-Wallis” ve “Pearson’s chi-squared??assessments were used. We found a positive correlation between loss of MLH-1 and PMS-2 expressions and the right-colon location K02288 poor and mucinous differentiation and dense lymphocytic infiltration. In addition loss of MSH-2 and MSH-6 expressions was correlated with the right-colon location poor and mucinous differentiation. We found a meaningful relationship between immunohistochemical markers and clinicopathological features usually observed in tumors with microsatellite instability. This obtaining may arouse suspicion for MSI. However the findings in our study must be supported with studies conducted in large series including molecular methods. value ≤ 0.05 was considered statistically significant in all statistical analyses. Results There were 124 men (66.7%) and 62 women (33.3%). The mean age was 66.69 ± 11.90 years (range 30 years). The numbers of cases according to clinicopathological parameters are shown in Table 1. Table 1 The numbers of cases according to clinicopathological parameters Correlation between clinicopathological features Statistically right colon location was correlated with mucinous adenocarcinoma (= 0.018) and presence of mucinous component (= 0.001). The ulcerous tumors were smaller (= 0.017) and their pathological tumor stage was higher (< 0.0001). In the patients with ulcerous tumors more lymph nodes were dissected (= 0.012). In the tumors arising in polyp size was bigger and the pathological tumor stage was lower (= 0.008) and multiple tumors were more common than in the tumors not arising in polyp (< 0.0001). Multiple tumors were together with polyps more frequently (= 0.001) and their pathological lymph node stage was more advanced (= 0.024). A statistically meaningful correlation was found between lymphocytic infiltration and accompanying polyp (= 0.042). In the poorly differentiated adenocarcinomas mucinous component (< 0.0001) lymphovascular (= 0.001) and perineural invasion (= 0.003) were more common. In addition as the differention deteriorated pathological tumor stage and lymph node metastasis increased (= 0.019; respectively). Less lymphovascular invasion (= 0.012) K02288 and lymph node metastasis (= 0.002) were detected in the tumors containing mucinous differentiation. Tumors with lymphovascular invasion had more advanced pathological tumor stage (= 0.001) and more lymph node metastasis (< 0.0001). Perineural invasion was not detected in any of the pT1 and pT2 tumors. Statistically perineural invasion correlated with surgical margin positivity (= 0.021) lymh node metastasis (< 0.0001) and pathological lymph node stage (< 0.0001). As the degree of lymphocytic infiltration increased the number of dissected lymph node increased too K02288 (= 0.030). Also there was a statistically meaningful Rabbit polyclonal to HMGCL. correlation between surgical margin positivity and regional lymph node metastasis (= 0.016) perineural invasion (= 0.021) and pathological tumor stage (= 0.016). In our study there K02288 was a statistically meaningful relationship between the number of dissected lymph nodes and lymph node metastasis (= 0.049). Correlation between immunohistochemical and clinicopathological features For all four immunohistochemical markers (MLH-1 MSH2 PMS-2 MSH-6) loss of expression was correlated with poorly differentiated and mucinous adenocarcinoma histology (< 0.0001 = 0.015 < 0.0001 < 0.0001 respectively). Also there was a correlation between localization to cecum and ascending colon and loss of PMS-2 and MSH-6 expression (< 0.0001 = 0.007 respectively). In the tumors with mucinous component loss of MLH-1 was observed more (= 0.003). Additionally in the cases which exhibited loss of MLH-1 and PMS-2 expression mucinous component (= 0.003 and < 0.0001) lymphovascular invasion (= 0.032 and < 0.0001) and intense intratumoral.