Evaluation of Stromal Myofibroblasts in Laryngeal Dysplasia and Invasive Squamous Cell Carcinoma

Malignant tumors consist of both carcinoma cells and tumor associated host cells. Host cells has started to receive more attention regarding their role in tumor progression such as invasion and metastasis. Fibroblasts that are incorporated in the tumoral stroma are called as peritumoral fibroblasts, reactive stroma, cancer-related fibroblasts or myofibroblasts. In general fibroblasts next to nich of cancer cells express alpha–smooth muscle actin (α-SMA) which is an important marker for differentiated myofibroblasts. Our aim is to investigate the role of α-SMA positive myofibroblasts in the development and progression of laryngeal carcinoma. The proportion of α-SMA positive myofibroblasts are scored from (1 +) to 3( +) in laryngeal dysplasia (n = 17) and microinvasive and invasive squamous cell carcinoma (n = 66). α-SMA expression in invasive carcinoma and dysplasia was analyzed statistically. No stromal myofibroblast was detected in mild dysplasia (score 0). Among 12 cases of moderate-severe dysplasia, in only 3 cases low α-SMA expression (score 1) was observed and in 9 cases there were no stromal myofibroblasts (score 0) were. In most cases of invasive carcinoma, high α-SMA expression (score 2, 3) was seen. α-SMA positive stromal myofibroblasts were significantly higher in invasive laryngeal squamous cell carcinoma compared to dysplasia (p < 0.05). Results of our study suggested that α-SMA positive stromal myofibroblasts play an important role in creating the permissive environment for tumor invasion in laryngeal squamous cell carcinoma. According to this data, we think that the presence of stromal myofibroblasts might be used as a helpful criterion in the differential diagnosis of true invasion and pseudoinvasion.