Growth hormone receptor expression in human colorectal cancer

The purpose of this study was to determine whether human colorectal cancer (CRC) expresses growth hormone receptor (GHR) and whether growth hormone plays an important role in the development and progression of human CRC. We investigated 42 specimens of CRC and normal colorectal mucous membrane, taken from the colon or rectum in a group of patients with CRC. Immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) technique were used to demonstrate GHR expression. The relationship between expression of GHR and clinical or pathological factors was analyzed. Immunohistochemical analyses revealed that GHR was expressed in human CRC (35/42; 83.33%) and appeared to be up-regulated compared to normal mucous tissue (29/42; 69.05%; P < 0.001). Contrasting sharply with the mostly strongly positive tumors, corresponding normal colorectal mucous membrane was negative or weakly positive. A significant inverse correlation was found between GHR expression and tumor stage (P = 0.002) and tumor differentiation (P = 0.036). In RT-PCR, 33 of the 42 tumors expressed GHR mRNA, while only 22 of the 42 normal colorectal mucous membranes did so. Our data demonstrate that GHR is frequently expressed in human CRCs and appears to be up-regulated compared to normal mucous tissue, thus supporting a possible role for growth hormone in CRC physiology.