Banca de QUALIFICAÇÃO: NATHALIA DA SILVA CARVALHO

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : NATHALIA DA SILVA CARVALHO
DATE: 09/05/2025
TIME: 14:00
LOCAL: Google meet
TITLE:

CHARACTERIZATION OF LOCAL AND SYSTEMIC IMMUNOSUPPRESSION IN DOGS WITH MELANOCYTIC NEOPLASMS

KEY WORDS:

immunomodulation; interleukin-10; macrophages; melanoma

PAGES: 25
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUMMARY:

Tumor evasion mechanisms have been the core of countless research aimed at finding new targets for immunological therapies. Melanomas are recognized immunogenic neoplasms and the observation of partial or complete regression of some tumors associated with marked infiltration by T lymphocytes contributes to this statement. However, this type of neoplasm also presents several mechanisms of tumor evasion, including the processes of immune mediation and secretion of immunosuppressive cytokines such as Interleukin-10 (IL-10). Additionally, components of the tumor microenvironment can positively or negatively influence the development of the neoplasm. The polarization of M2 macrophages in the inflammatory infiltrate has a pro-tumorigenic action, as these cells secrete cytokines with anti-inflammatory action and which stimulate local neovascularization. This work aimed to characterize possible local and systemic immunosuppression that can be used as prognostic markers in dogs with melanocytic neoplasms. Immunohistochemical analyzes were performed to investigate the expression of Ki-67, IL-10 in subpopulations of M2 macrophages using the anti-CD-206 antibody that may be infiltrated in the neoplasia in regional lymph nodes and internal organs when possible. For this, paraffin-embedded fragments of melanocytic neoplasms in dogs (oral and cutaneous) and the respective regional lymph nodes were used. For research into internal organs, priority was given to necropsies of dogs diagnosed with malignant melanomas and that had died as a result of the disease or were euthanized as recommended by the responsible clinician. To date, data have been collected on 25 cases diagnosed in dogs, four of which were melanocytomas and the rest melanomas. Regarding epidemiology, 10 affected females, 15 males, all animals were adults between seven and 17 years of age. Thirteen cases were in the skin, 11 in the oral cavity and one was observed in the brain with no previous report of neoplasia in another site. Among the melanomas, 19 were of the mixed type, four epithelioid and two fusiform. In 19 of the 25 cases, pleomorphism was moderate to marked and in 14 cases, more than 10 mitotic figures were observed in 10 higher magnification fields (Obj. 40x). To date, immunohistochemistry with the Ki-67 antibody has shown immunoreactivity in 16 cases, all of the malignant variant. In five cases, a growth fraction greater than 15% was observed both at the site of origin (three in the oral cavity and two in the skin) and in the regional lymph node, one case (site of origin in the oral cavity) with a growth fraction greater than 15% only at the site of origin, another four cases with a high growth fraction only in the metastatic lymph nodes (two sites of origin in the oral cavity and two in the skin) and in one case, a high growth fraction determined by Ki-67 was observed in the lung (with site of origin in the oral cavity). CD206 expression was observed in seven cases, with intratumoral and peritumoral distribution. Other analyzes are in progress.

COMMITTEE MEMBERS:
Interna - 2572430 - CRISTIANE DIVAN BALDANI
Interna - 2606155 - VIVIAN DE ASSUNCAO NOGUEIRA CARVALHO
Externa à Instituição - GABRIELA DE CARVALHO CID - UFRRJ
Externa à Instituição - MARIANA CORREIA OLIVEIRA - UES
Externa à Instituição - SAMAY ZILLMANN ROCHA COSTA