Expression of Laminin in Oral Squamous Cell Carcinomas

Background and objectives: Laminin is a significant basement membrane (BM) glycoprotein, the expression of which reflects BM integrity more precisely than do other ECM proteins. The present study aimed to evaluate laminin expression in oral squamous cell carcinomas OSCC and to determine any associations with clinico-pathological parameters (surgical margin status, lymph node involvement, survival and recurrence). Methods: Laminin expression was evaluated in 31 cases of biopsy-proven OSCC by immunohistochemical staining and its association with prognosticators and the Brynes grading system was determined by appropriate statistical analysis. Results: We observed a significant increase in linear staining pattern (p<0.001) at the tumour-host interface in well-differentiated OSCC cases, in contrast to poorly differentiated lesions which exhibited intense cytoplasmic expression within tumour cells. Higher cytoplasmic laminin expression was seen in 33.3% of cases with involved surgical margins and 69.2% of cases with lymph node metastasis (along with weak/absent staining of laminin around the tumour-host interface – Basement membrane around tumour islands). Similarly, in 60% of the cases who died and in 81.8% of cases with tumour recurrence, moderately intense cytoplasmic laminin expression was seen within tumour cells. On comparing variables of the Brynes grading system, significant cytoplasmic expression of laminin was linked with mild inflammation (p<0.0016) and increased mitotic activity (p<0.008). Conclusion: Based on these observations, immunohistochemical expression of laminin might be useful to evaluate histological differentiation and aggressiveness of OSCCs.