Lymph nodes as a pre-metastatic niche for oral squamous cell carcinoma

Abstract

Background Pre-metastatic niche (PMN) is a new concept in the process of metastasis defined as tumour microenvironment at the future metastatic site which is established by the tumour as a preparation before the arrival of the disseminated tumour cells. Certain cells and cytokines have been reported to be a key factor in building these niches. To date, there is no single study that has investigated the PMN in the oral squamous carcinoma (OSCC). My hypothesis is that IL17, IL22, IL23 and STAT3 play part in the formation of PMN of metastatic OSCC. Aim: To compare the expression of STAT3 and cytokines (IL22, IL23 and IL17) between positive and negative lymph nodes from OSCC. Methods: A total of 36 formalin fixed paraffin embedded (FFPE) tissue specimens were obtained from the Malaysian Oral Cancer Database & Tissue Bank System (MOCDTBS). Sample were divided into two groups. Positive lymph nodes were those with histological evidence of metastatic OSCC while negative nodes were those with no sign of metastasis. Th expression of IL17, IL22, IL23 and STAT3 was investigated using immunohistochemistry (IHC). Gene expression was done using Real time polymerase chain reaction (RT-PCR) to validate the results. Image J was used to count the number of positively staining cells. SPSS was used to analyze the data. Results: IHC results shows that the expression of IL22, IL23 and STAT3 was significantly higher in the negative lymph nodes when compared with the positive group which proof our hypothesis. However, the difference in gene expression was not significant. Conclusion: My results suggest that negative lymph nodes can be a PMN for the OSCC. In addition, IL22, IL23 and STAT3 can be responsible at least partially for the formation of this PMN.