Impact of stromal CD45RO+ immune cells on proliferation and dedifferentiation in node-negative squamous cell carcinomas of cheek mucosa.

Background: The most fundamental trait of cancer cells involves their ability to sustain chronic proliferation. Tumors have a complex cellular ecology that establishes the malignant potential of the tumor. In these ecosystems, innate immune cells are highly represented. Many contradictory reports have been published regarding the impact of tumor-infiltrating immune cells on proliferation of the tumors.

Aim: This study aims to assess the impact of CD45RO+ve immune cells on proliferation and dedifferentiation of node-negative squamous cell carcinomas of cheek mucosa (SCC-CM).

Materials And Methods: Thirty formalin-fixed paraffin-embedded tissue blocks of previously diagnosed node-negative SCC-CM subclassified as Grade I SCC - 10 cases; Grade II SCC - 10 cases; and Grade III SCC - 10 cases (Broders' classification - 1927). Immunohistochemistry performed on each selected tissue section using anti-p53 and anti-CD45RO as primary antibodies. Semi-quantitative analyses performed for all the tissue sections to assess the p53 and CD45RO expression. p53:CD45RO expression ratio calculated. The data were statistically analyzed using GraphPad Prism 5 for Windows.

Results: Our results showed statistically significant increase (P = 0.0006) in p53 expression and decrease (P = 0.0044) in CD45RO+ immune cell response with the decrease in differentiation of SCC-CMs using Fisher's exact test and statistically significant increase (P < 0.001) in p53:CD45RO expression ratio with decrease in differentiation using one-way ANOVA.

Conclusion: Based on all these findings from the present study, we perceive the following findings. In node-negative SCC-CMs, CD45RO+ immune cells play a possible role in controlling the dedifferentiation of the tumor and in limiting the proliferative potential of the tumor cells which are tumor antagonistic in nature.