Role of neurotransmitter Substance P in progression of oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is the most frequent type of head and neck cancers. In the present study, we evaluated the expression and distribution of Substance P (SP) in different grades of OSCC and role of SP in its proliferation and progression. Forty OSCC biopsies were immunohistochemically analyzed by using SP antibody, including 29 male and 11 female cases. 35% were well differentiated, 35% moderately differentiated and 30% poorly differentiated OSCC. The majority of patients were in the age range of 41–80 years. 62% of the cases were positive for SP. SP positivity was expressed in the cytoplasm of the tumor cells. Most of the positive cases were from the tongue region. 93% of moderately differentiated, 92% of poorly differentiated and 8% of well-differentiated carcinomas were SP-positive, but SP expression intensity was highest in poorly differentiated cases (+3). More positive patients were males (68.96% of all male patients) with moderately and poorly differentiated OSCC. Among all positive cases, 48% were poorly differentiated, 48% moderately differentiated and 4% well differentiated. Strong expression of SP in poorly and moderately differentiated cases suggests a role of SP in the progression and development of tumor. Expression of SP in the current study increased as the proliferation of cells increased. Prevalence of oral cancer in males may be due to the fact that they smoke and use pan, chewing gum, beetle nut etc. in this region. SP antagonists can help in the reduction and inhibition of oral cancer. SP has a diagnostic value with sensitivity of 92.5% and specificity of 93.7%. The positive predictive value is 96.2% and the negative predictive value 88.2%.