Infrastructure of the telocytes from tumor stroma in the skin basal and squamous cell carcinomas.

In this paper, we focus our interest on the ultrastructure of telocytes (TCs) present inside of tumor-stroma in basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Tumor-stroma cooperation is necessary for tumor growth, invasive behavior and ectopic development of microtumors. There is a plethora of reports about the role of different stromal cell types in tumor evolution in the human body. In this line, almost nothing is known about the recently identified interstitial cell type called telocyte (TC). To our best knowledge, this is the first study to publish TCs in malignant tumors, namely BCC and SCC. Here, we described the infrastructural aspects of TCs as well as their relationships with other tumor stroma components. TC from the tumor stroma has cell body where the nucleus is located and exhibits two (rarely more) very long cell extensions of tens (over 60-100 μm) termed telopodes. A telopode appears as an alternation of very thin segments called podomers and dilated segments called podomes, which accommodate mitochondria, rough endoplasmic reticulum, cytoskeleton, caveolae, as well as coated vesicles. TCs establish homocellular junctions leading to a 3-D network inside of peritumoral stroma. TCs may play an important role in intercellular signaling via stromal synapses and shed microvesicle transfer. Comparative evaluation with normal dermal skin showed that telocytes from tumor stroma have a very restraint number of heterocellular junctions. The limitation of TCs heterocellular junctions suggests a possible involvement in induction of cell-cell communication alterations into the peritumoral stroma and, consequently, into the whole tumor mass.