Overexpression of Gli1 in cancer interstitial tissues predicts early relapse after radical operation of breast cancer

Objective

To investigate whether Gli1 expression is important in relapse after radical operation of breast cancer.

Methods

Using immunohistochemistry, Gli1 expression was analyzed in human primary breast cancer (n=284) and paracancerous tissues (n=20), and also in local lymph nodes (n=28) and metastatic lymph nodes (n=28).

Results

Initial analysis of Gli1 expression in a small cohort of 20 breast tumors and their paracancerous tissues showed a tendency towards Gli1 overexpression in breast cancer tissues (P<0.001). Further, Gli1 expression in 284 breast cancer tissue samples was analyzed and a significant correlation was found between increased expression of nuclear Gli1 and unfavorable recurrence-free survival (RFS) (P<0.05). The nuclear expression of Gli1 in metastatic lymph nodes following relapse after radical operation was much higher than that in the local lymph nodes of primary carcinoma (P<0.05). Most interestingly, the expression of Gli1 was much higher in the interstitial tissues of the relapsed group than of the non-relapsed group (P<0.001).

Conclusions

Breast cancer shows a high prevalence of Gli1 expression, which is significantly correlated with aggressive features and unfavorable RFS. Nuclear Gli1 overexpression, especially in the interstitial tissues, signified early relapse after radical operation of breast cancer.