Expression and clinical significance of Shh/Gli-1 in papillary thyroid carcinoma

The Sonic Hedgehog (Shh) pathway affects cancer initiation, progression, and metastasis, but its role in papillary thyroid carcinoma (PTC) remains elusive. To characterize expression and clinical significance of Shh and the transcription factor Gli-1-the key elements of the Shh pathway in PTC tissues-we immunohistochemically examined Shh/Gli-1 expression in PTC tissues from 142 patients, along with adjacent non-cancerous tissues as controls. We reviewed 142 patients' clinical characteristics and analyzed their relationship with expression of Shh/Gli-1. Shh and Gli-1 were expressed in 64.1 % (91/142) and 47.9 % (68/142) in PTC tissues, respectively, compared with 16.9 % (24/142) and 9.2 % (13/142) of adjacent non-cancerous tissues. Gli-1 expression was significantly associated with patients' ages (P<0.05) and lymph node metastasis (P<0.01). Increased Shh and Gli-1 expression was significantly associated with tumor-node-metastasis (TNM) stage (P<0.01). Shh and Gli-1 were expressed in 79.2 and 60.4 %, respectively, of PTC tumors larger than 10 mm. Shh was significantly associated with tumor size (P<0.01). Shh and Gli-1 were expressed in 72.5 and 65.2 %, respectively, of patients with lymph node metastasis. Overall, we found increased expression of the main initiator Shh and transcription factor Gli-1 in Shh pathway in PTC tissues. The expression of Shh/Gli-1 was significantly associated with tumor size, clinical staging, and lymph node metastasis, indicating that aberrant activation of the Shh pathway is important to PTC occurrence and progression. Potentially, Shh/Gli-1 could be a diagnostic indicator and a marker of therapeutic response.