Expressão de micrornas em neoplasias mamárias de gatas

Abstract

Feline mammary neoplasms are frequently malignant and biologically aggressive, supporting the investigation of markers that may improve tumor characterization. This study described clinicopathological features of cats with mammary neoplasia and explored RT-qPCR quantification profiles of selected microRNAs according to contraceptive history. The study sample comprised six cats: four with mammary neoplasia, classified as no-contraceptive (FSA; n=2) or contraceptive-exposed (FCA; n=2), and two classified as controls (FC; n=2). Tumor characterization used the four neoplastic cases, whereas molecular analysis included all six animals with RT-qPCR results. The targets were let-7a, miR-29b, miR-191, miR-200b, miR-200c, miR-484, miR-10b, and miR-21. Tumor-bearing cats had a mean age of 10.75 years, a median age of 10 years, and a range of 8–15 years. Maximum tumor dimension ranged from 2.20 to 7.00 cm; two of four lesions were ulcerated, both in FSA. Histopathological diagnoses included solid carcinoma, grade II/III solid carcinoma, cribriform carcinoma, and grade II tubulopapillary carcinoma. Technical replicates were consolidated at the animal level, and Cq values equal to zero were treated as missing in the calculations. Mean Cq values for FC/FSA/FCA were, respectively: let-7a 19.61/17.57/23.71; miR-29b 25.79/31.65/31.22; miR-191 25.11/28.28/31.18; miR-200b 25.53/26.71/26.70; miR-200c 25.47/30.72/30.54; miR-484 25.87/27.21/28.74; miR-10b 29.77/29.35/29.57; and miR-21 26.03/28.04/28.97. Because a higher Cq corresponds, under comparable conditions, to a lower starting target quantity, the data were interpreted as an exploratory quantification profile. The ΔΔCq method was not applied because a validated endogenous normalizer and assay efficiencies were not available. The findings demonstrate clinical, histological, biological, and technical heterogeneity and support further investigation, but they do not demonstrate differential expression or a causal effect of contraceptive exposure.