Significance of Myofibroblast Appearance at the Invasive Front in Early-Stage (T1/T2) Oral Squamous Cell Carcinoma (OSCC): A Preliminary Report

Abstract

Background: The aim of the present study was to assess the frequency of stromal myofibroblast appearance, and to further clarify whether myofibroblasts influence tumor suppression or progression within stromal desmoplastic reaction. To our knowledge this is the largest study in the English literature examining the role of stromal myofibroblast proliferation in oral squamous cell carcinoma (OSCC) and the first addressing its prognostic significance in early-stage oral cancer with a clinically negative neck. Materials and methods: Biopsy materials from 89 patients with early stage (T1/T2) OSCC were retrospectively analysed. Frequency of myofibroblasts within desmoplastic stroma was assessed immunohistochemically and compared with other clinically and pathological factors. Results: Immunohistochemical reaction for α-smooth muscle actin showed positive cells in stroma of 76.4 % (n = 68) of OSCC. Abundant presence of myofibroblasts in the tumor stroma was significantly correlated with presence of lymph node metastases (P < .001), distant metastases (P = .03), perineural invasion (P= .01) and stromal desmoplastic reaction (P < .001). Patients whose specimens demonstrated abundant myofibroblasts had a disease specific survival rate at 5-years of 73.3% compared with 92.4% for patients with scanty myofibroblasts which is statistically significant (P= .05). Presence of myofibroblasts was not associated with T stage, local and regional recurrence, tumor cellular differentiation and mode of invasion. At the end of the study, 16 of the patients (18%) had died of disease recurrence. Follow-up information was available for all patients and ranged from 9 to 159 months (mean 60). Conclusion: Together, our data demonstrate that abundance of myofibroblasts leads to a more aggressive phenotype of the OSCCs resulting in significantly increased presence of lymph node and distant metastases as well as lower survival rates. Further investigations of stromal interactions and phenotypic characteristics of myofibroblasts at the invasive front are needed in order to provide new diagnostic markers or anti-cancer therapeutic modalities. Disclosure: All authors have declared no conflicts of interest.