Abstract: Objective To explore the expression of G protein-coupled receptor，family C，group 5，member A（GPRC5A），signal transducer and activator of transcription 3（STAT3） and suppressor of cytokine signaling 3（SOCS3） in colorectal cancer tissues and their relationsip with clinicopathological features. Methods Totals of 76 colorectal cancer tissues  and 30 adjacent normal tissues were enrolled. Immunohistochemistry was used to detect the expressions of GPRC5A，SOCS3 and STAT3 in different tissues，and the relation ship between the expression and clinicopathological features and their correlation were analyzed by spearman correlation analysis. Results The positive expression rates of GPRC5A and STAT3 in colorectal cancer tissues were significantly higher than those in adjacent normal tissues（59.2% vs 33.3%，P＝0.016；69.7% vs 30.0%，P＝0.001），but the positive expression rate of SOCS3 was significantly lower than that in adjacent normal tissues（38.2% vs 80.0%，P＝0.001）. The expression of GPRC5A was significantly associated with pathological differentiation，lymph node metastasis，and TNM staging of colorectal cancer（P<0.05）. The expression of SOCS3 and STAT3 were significantly associated with pathological differentiation，depth of invasion，lymph node metastasis，and TNM staging of colorectal cancer（P<0.05）. The Spearman correlation analysis showed that SOCS3 protein expression were negatively correlated with STAT3 expression and GPRC5A expression（r=－0.308，P=0.007；r=-0.340，P=0.003），and GPRC5A protein expression was positively correlated with STAT3（r=0.327，P=0.004）. Conclusions GPRC5A is highly expressed in colorectal cancer tissues and may negatively regulate the expression of SOCS3 and positively regulate the expression of STAT3. GPRC5A，SOCS3 and STAT3 may be closely related to the occurrence and development of colorectal cancer.

Key words:  , Colorectal cancer；GPRC5A；SOCS3；STAT3；Immunohistochemistry