Role of signal transducer and activator of transcription 3 in cutaneous squamous cell carcinoma

Abstract

Objective To assess the role of signal transducer and activator of transcription 3 (STAT3) in cutaneous squamous cell carcinoma (cSCC). Background cSCC is considered the second most frequent type of nonmelanoma skin cancer. The Janus kinase-STAT pathway plays a significant role in the proliferation and survival of various cancer cells. Between seven mammalian STAT proteins, continuous activation of STAT3 is commonly observed in several cancer cells. Patients and methods This prospective and retrospective case–control study was conducted on 48 cases with cSCC and 47 age-matched and sex-matched apparently healthy participants. All sections were immunohistochemically stained for the STAT3 antibody. Results All controls showed significant STAT3 nucleo-cytoplasmic localization in the epidermis and the dermis, whereas in cSCC, most cases of nonmelanoma skin cancer showed cytoplasmic STAT3 expression in the epithelium and the surrounding stroma (P < 0.001 for both). STAT3 overexpression was noted in cSCC in comparison with the control group (P = 0.007). A significant relationship between the STAT3 epithelial Histo-score and high grade (P = 0.001) and advanced stage (P < 0.001) of cSCC was noted. Conclusions Cytoplasmic localization of STAT3 could play a tumor-promoting role in the pathogenesis of cSCC. Moreover, STAT3 overexpression might be incriminated in the progression of cSCC. This could be very attractive in the development of new anticancer therapy using STAT3 inhibitors.