Differential infiltration of neutrophils in T1-T2 versus T3-T4 oral squamous cell carcinomas: a preliminary study

Recent studies have pointed towards a role of tumour-infiltrating neutrophils in cancer biology. Investigations on oral squamous cell carcinoma have indicated a possible association with clinical characteristics. This study aimed to evaluate neutrophil infiltration and the neutrophil/lymphocyte ratio in the central areas and invasive front of oral squamous cell carcinomas at different T stages, and their association with clinicopathological features and patient outcome.

Clinical information was retrieved from the charts of patients who had undergone surgical treatment. Samples of the excised tumours were subjected to immunohistochemical analysis for CD66b and CD3. Semi-quantitative analysis was performed in the intratumoural region and in the invasive front. Appropriate statistical tests were used for evaluating the data, including Kaplan-Meier survival analysis and the log-rank test. A p value of less than 0.05 was considered significant.

T3-T4 tumours presented higher CD66b infiltration in the intratumoural region and higher CD66b/CD3 ratios in the invasive front than T1-T2 lesions (p < 0.05). There was a strong inverse correlation between CD66b and CD3 in the invasive front of T3-T4 tumours (r = -0.712, p < 0.05). Comparisons of CD66b and the CD66b/CD3 ratio according to N status, tumour location, recurrence, inflammation grade, and histological grade did not reach statistical significance. Survival analysis also did not show any significant differences.

The present study showed different degrees of neutrophil infiltration between T1-T2 and T3-T4 oral cancers, with higher indexes in the advanced lesions. However, there was no association with clinicopathological features or with time to recurrence.