2017 ACVIM Forum Research Abstract Program

The perceived incidence and management of CIVI in dogs widely differs. Dogs receiving chemotherapeutics with currently perceived lower potential for CIVI may also benefit clinically from treatment with antiemetics and/or appetite stimulants. Further research to understand the true incidence and clinical impact of CIVI will contribute to development of guidelines to appropriately manage these effects in dogs. Cutaneous lymphoma represents 1% of skin tumors in dogs and is classified in epitheliotropic and nonepitheliotropic. Unlike the other anatomical forms of lymphoma, cutaneous lymphomas have a low response to the treatment, and dogs with nonepitheliotropic lymphoma have a lower survival time when compared to dogs with epitheliotropic form. The resistance of neoplastic cells to cytotoxic drugs is the major cause of failure of chemotherapy in cancer and one of multiple drug resistance mechanisms (MDR) is the active drug efflux mediated by ATP-Binding Cassette superfamily (ABC). Among these transporters is P-glycoprotein (ABCB1).The aim of this study was to investigate ABCB1 immunoexpression in cutaneous epitheliotropic and non-epitheliotropic lymphoma. Immunohistochemistry was performed in 18 paraffinembedded tumor samples of cutaneous lymphoma in dogs (11 nonepitheliotropic and 7 epitheliotropic) using CD20 and CD3 markers for immunophenotyping and ABCB1 antibody (C494 -Enzo Life Sciences Ã’ ). It was found 5 epitheliotropic T-cells and 2 B-cells and 10 nonepitheliotropic T-cells and 1 B-cell lymphoma. Two samples of epitheliotropic lymphoma were negative for ABCB1 and the median percentage of labeled cells was 20% (0-40%) whereas in nonepitheliotropic lymphoma, all cases were positive for ABCB1 and the median percentage of labeled cells was 50% (20-90%) and statistical analysis showed a significant difference expression of this marker (P = 0.0162). In conclusion, the majority of cases with cutaneous lymphoma expressed P-glycoprotein and the subtype nonepitheliotropic showed higher labeled cells than epitheliotropic. Intestinal lymphoma is the main anatomical form of lymphoma diagnosed in cats. Cell proliferation indicators as Ki-67 expression and mitotic index may be important in assessing the clinical behavior of the tumor and to determine the degree of malignancy. The objectives of this study were to determine the expression of Ki-67 and mitotic index in intestinal lymphoma of cats and its relation with overall survival time. Forty-seven samples of cats with intestinal lymphoma were studied and immunohistochemical was performed for: CD3, PAX5 and Ki-67. The analysis of Ki-67 was made by counting 1,000 infiltrating lymphocytes in the tumor microenvironment and mitotic index was ranked as mild, moderate or high, by the evaluation of 10 microscopic fields at 409. The results showed a significant difference in the immunohistochemical expression of Ki-67 in B and T-cell Lymphoma (P = 0.001) with a median of 47.2% and 8.5%, respectively. The same was observed when comparing the histological type (lymphoblastic and lymphocytic), with a median of 40.5% and 8.2%, respectively (P = 0.002). Regarding mitotic index, two cats with lymphoblastic B-cell and one with lymphoblastic T-cell lymphoma showed high expression, while three animals showed moderate expression and the majority of cases, 41 animals (87.2%) had mild expression. In conclusion, Ki-67 expression was a better proliferative marker when compared to mitotic index in cats with intestina