Expression and clinicalsignificance of Sonic hedgehog mRNA and protein in colorectal carcinoma

Abstract

：Objective To evaluatethe expression of Hedgehog signaling pathway related Sonic hedgehog (SHH) gene incolorectal carcinoma (CRC) and to explore its clinical significance. Methods BetweenDecember 2008 and April 2009, 43 specimens of fresh CRC tissues and adjacent tissues (＞10cm away from the cancer margin) were collected and detected for their expressions of SHHmRNA and proteins with RT-PCR and immunohistochemistry (Envision method), and comparedwith 20 specimens of normal colorectal tissues from non- CRC patients as controls. Theassociations of SHH mRNA and proteins expressions and clinicopathological variables wereanalyzed. Results Gel-imaging analysis displayed a 280 bp band in SHH mRNA-positivespecimens in consistency with theoretical value, which was not seen in SHH mRNA-negativespecimens. The rate of SHH mRNA expression in CRC tissues (27.9%, n=12) was notstatistically different from that in the adjacent tissues (18.6%, n=8) (P＞0.05), but the both were significantly higher than that in the normal mucosa (0%, n=0) (all P＜0.05).The expression intensity of SHH mRNA was significantly higher in CRC tissues than that inthe adjacent tissues (P＜0.05) but not detected in normal colorectal tissues(P＜0.05). Immunohistochemistry demonstrated positive expression of SHHproteins in both CRC tissues and adjacent tissues, appearing as yellow-brown particleswith unstained background in the cell membrane and cytoplasm. The expression of SHHprotein was negative in the cell membrane of normal colorectal mucosa. The rate of SHHprotein expression in CRC tissues was remarkably higher than that in normal colorectalmucosa [25.6% (11/43) vs 0% (0/20) , P＜0.05]. There was nostatistical difference in the positive rate of SHH protein expression between CRC andadjacent tissues, and between adjacent tissues and normal colorectal mucosa (all P＞0.05).The CRC tissues showed the highest intensity of SHH protein expression, followed byadjacent tissues and normal mucosa (all P＜0.05). No significantassociation was found between intensity of SHH mRNA or protein expression in CRC tissuesand the variables such as age, gender, clinical staging, site of tumor, depth of tumorinvasion and pathological classfications (all P＞0.05). Conclusion The SHH mRNA and protein expressions areshown to be significantly enhanced in CRC tissues but not associated with clinical orpathological variables. Key words: Sonic hedgehog; Colorectal neoplasms; Reversetranscriptase polymerase chain reaction; Immunohistochemistry; Clinical significance