Peritumoral inflammatory reaction in non-melanoma skin cancers - histological and immunohistochemical study

Non-melanoma skin cancers (NMSCs) are the most frequent types of cancer in white skin populations, all over the world. In the last 40 years, there was observed a rapid increase of their incidence, because of the UV radiations exposure and weather changes. Although its morbidity is a relatively modest one, the direct social costs of NMSCs are quite substantial due to a high incidence. Due to these reasons, numerous studies try to clarify the etiopathogenic mechanisms of NMSCs, to elaborate treatment and prevention measures. In the last years, a special attention was given to the relation between inflammation and skin cancer. In our study, we performed a histological and immunohistological evaluation of the inflammatory reaction on a number of 73 surgical exeresis pieces coming from the patients diagnosed with NMSCs. Of these, 21 were squamous cell carcinomas (SCCs) and 52 basal cell carcinomas (BCCs). The peritumoral inflammatory reaction in NMSCs was an extremely variable one in intensity and distribution, from one case to another and even from one area to another within the same tumor, thus proving the complexity of the relations between tumor cells and cells of the immune system. By comparing the intensity of the inflammatory reaction between the two main types of NMSCs, there was observed that in SCCs the inflammatory reaction was more intense in comparison to BCCs. Also, in SCC there was highlighted a more abundant inflammatory infiltrate in poorly differentiated carcinomas, in comparison to the well-differentiated ones. The presence of the immune system cells (T-lymphocytes, macrophages, mast cells) among the tumoral cells, in a direct contact with these, makes us believe that between the two categories of cells there may appear mechanisms of intercellular oommunication, distinct from the mechanisms of paracrine signaling.