MAST CELLS INFILTRATION IN PREMALIGNANT TONGUE LESIONS UPON TTP ABLATION IN CONDITIONAL TRANSGENIC MICE.

DARIO FERRI; MARINA AYRE; VALERIA SNCHEZ; EDITH KORDON; MARÍA LAURA PAPARELLA; ANA RAIMONDI

Congreso; Reunión Anual SAIC 2019; 2019

Oral squamous cell carcinoma (SCC) is the sixth most common cancer worldwide and tongue SCC is the most common oral malignancy. RNA-binding proteins (RNA-BP) that regulate transcript stability play a key role in disease pathogenesis. Tristetraprolin (TTP) is a RNA-BP that regulates proinflammatory mediators which promote tumorigenesis. We have previously developed TTP knockout mice for oral cavity (TTP-KO:K14-CreERtam/TTP-/-). TTP-KO mice developed dysplastic lesions in the tongue along with inflammatory cells infiltration in the connective tissue. TTP-KO mice were bred with a K-rasG12D line, obtaining compound mice (K14-CreERtam/TTP-/-/K-rasG12D+/-). They developed a complete oral phenotype with more aggressive histologic features and persistent inflammatory infiltrates. Compound mice heterozygous (het) for TTP showed a different phenotype. Here, to study the inflammatory infiltrate in these premalignant lesions we characterize their cell composition. We performed immunohistochemistry for S100A (monocytes, neutrophils, macrophages) and 2 different staining for mast cells: alcian blue-safranin (AB-S) and toluidine blue (TB). We found S100A positive cells in the tongues of TTP-KO, compound and het-compound mice. These cells were distributed equally between groups. AB-S positive cells were found in the connective tissue of the tongues in all experimental groups. However, the distribution and the amount of these cells were not homogenous. We performed TB staining and quantified positive cells (cell/area). We found a statistically significant increase in TB positive cells in TTP-KO (19.8 ± 1.8) compared with compound (11.04 ±2.01), het compound (6.26 ± 1.9) and wild type tongues (10.68 ± 4.27), ANOVA p