Introduction/Background Neutrophils play a key role in immune protection against bacterial threats. In cancer, these heterogeneous cells can exert pro- or anti-tumour functions. This study aimed to characterise the putative effect of neutrophil recruitment on vulvar squamous cell carcinoma (VSCC) progression.

Methodology Clinical material was obtained from 89 patients with VSCC. The abundances of CD66b, the neutrophil activation marker as well as cathepsin G (CTSG), neutrophil elastase (ELANE), and proteinase 3 (PRTN3), the main neutrophil serine proteases (NSPs) were analysed by immunohistochemistry (IHC) in VSCC tumours. Quantitative polymerase chain reaction (qPCR) were used to detect the 12 selected bacterial species in VSCC.

Results High abundance of CD66b in VSCC tumours was found to relate to poor survival of patients with VSCC. The selected NSPs were shown to be expressed in vulvar tumours, also within microabscess. The increased numbers of microabscesess were also correlated with poor survival in VSCC patients. The presence of Fusobacterium nucleatum and Pseudomonas aeruginosa in the tumours was found to be associated with a shorter time to progression in VSCC patients.

Conclusion Our results show that neutrophils seem to be generally pro-tumoral cells in VSCC. It can be hypothesised that infiltration of neutrophils may be permissive for tumour-promoting bacteria in vulvar tumours.

Disclosures The work supported by the Foundation of Count Jakub Potocki, Grant Number UMO-103/21.