Expression and Clinical Significance of Hedgehog Signaling Pathway Related Components in Colorectal Cancer

Aim: To investigate the expression of three components of the Hedgehog (Hh) signaling pathway (SHH,SMO and GLI1) in human colorectal cancer (CRC) tissues and evaluate their association with clinicopathologiccharacteristics of the patients.
Methods: Fresh tumor tissues and matched tissues adjacent to the tumor werecollected from 43 CRC patients undergoing surgery. Normal colorectal tissues from 20 non-CRC cases werealso sampled as normal controls. The expression of SHH, SMO, GLI1 mRNAs was assessed by RT-PCR andproteins were detected by immunohistochemical staining. Associations with clinicopathological characteristicsof patients were analyzed.
Results: SHH mRNA was expressed more frequently in tumor tissues than in normaltissues, but the difference did not reach significance in comparison to that in the adjacent tissues. SMO and GLI1mRNAs were expressed more frequently in tumor tissues than in both adjacent andnormal tissues. The expressionintensities of SHH, SMO, GLI1 mRNA in tumor tissues were significantly higher than those in adjacent tissuesand normal tissues. Proteins were also detected more frequently in tumors than other tissues. No significantlinks were apparent with gender, age, location, degree of infiltration or Dukes stage.
Conclusion: Positive ratesand intensities of mRNA and protein expression of Hh signaling pathway related genes SHH, SMO, GLI1 werefound to be significantly increased in CRC tissues. However, over-expression did not appear to be associatedwith particular clinicopathological characteristics.