Prognostic significance of Substance P/ Neurokinin 1 receptor and its association with hormonal receptors in breast carcinoma

To evaluate the expression and Immunolocalization of Substance P (SP)/ Neurokinin-1 Receptor (NK-1R) in Breast Carcinoma (BC) patients and it’s association with routine proliferative markers (ER, PR, HER2/ neu and Ki-67). Methods A cross-sectional study was performed on 34 cases of BC. There were 23 cases of group A (Grade III), 8 of group B (Grade II) and only 3 cases of group C (Grade I). Age range comprised of patients from 20-80 years and the mean age of patients was 45.74 years. HE, ER, PR, HER2 and Ki-67 staining was performed as routine biomarkers. Samples were then processed for immunomarkers study of Substance P and NK-1R immunohistochemistry was performed for few cases. Results 14/23 cases (61%) of group A, 7/8 cases (88%) of group B and 2/3 (67%) cases of group C were SP positive. Overall, strong staining (≥ 10% tumors cells), labeled as “3+”, was observed in 9/14 (64.2%) cases of group A and 1/8 (12.5%) case of group B. Moderate staining labelled as “2+” (in ≥ 10% tumor cells) was observed in 3/14 (21.4%) cases of group A, 4/8 (50%) cases of group B. weak positive staining “1+” was observed in only 2/14 (14.28%) cases of group A, 2/8 (25%) cases of group B and all 2/2 (100%) cases of group C. Conclusions SP and NK-1R is overexpressed in breast carcinomas and there is significant association between grade of tumor and their overexpression. It may serve as a novel biomarker for grading of BC. We also suggest that NK-1R antagonists as a potential therapeutic strategy to inhibit and manage BC. Key Points Immunohistochemical expression of Substance P and Neurokinin 1 Receptor in breast carcinoma tissue was evaluated It was strongly expressed in grade III, with maximum intensity It may be investigated further for its role as prognostic and diagnostic marker Therapeutic potential of Neurokinin-1 Receptor antagonists must be explored