Immunohistochemical Study of Tumour-Associated Macrophages Using CD68 and CD163 in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is one of the most prevalent cancers in India. Significant research over the last 10 years has revealed that the inflammatory tumour microenvironment is crucial to the development of OSCC. Macrophages account for 30-50% with subtypes M1 and M2, hence called as tumour-associated macrophages (TAMs). It was a laboratory-based observational study conducted on 88 histologically proven cases of OSCC to determine the immunohistochemical expression of TAMs and to find its association with lymph node metastasis and TNM staging. Screening for lymph node metastasis, grading and TNM staging were done according to the new AJCC staging criteria followed by immunohistochemical staining of the same using CD68 and CD163. The mean age observed was 48.5 years with a female preponderance. Strong cytoplasmic positivity for CD68 was noted in 21.5% of cases whereas strong membranous positivity for CD163 was noted in 70% of cases. 43.18% of cases had nodal involvement. 5.6%, 17%, 34% and 43.4% of cases belonged to TNM stages I, II, III and IV respectively. CD68 positivity score was higher in node negative cases. Increased CD163 TAMs score was linked to lymph node positivity (p = 0.003) and higher TNM stages (p = 0.014). When assessing OSCC, the important role of the tumour microenvironment must be taken into account. TAMs show promise as a marker for tumour aggressiveness and as possible targets for immunotherapy.