P-glycoprotein (P-gp/ABCB1) and breast cancer resistance protein (BCRP/ABCG2) expression are frequently related to multidrug resistance (MDR) in neoplastic cells. Canine inflammatory and grade III noninflammatory mammary carcinomas (IMC and non-IMC) are aggressive tumors that could benefit from chemotherapy. This study describes the immunohistochemical detection of P-gp and BCRP in 20 IMCs and 18 non-IMCs from dogs that had not received chemotherapy. Our aim was to determine if P-gp and BCRP expression was related to the "inflammatory" phenotype, to establish a basis for future studies analyzing the response to chemotherapy in dogs with highly malignant mammary cancer. Immunolabeling was primarily membranous for P-gp with a more intense labeling in emboli, and immunolabeling was membranous and cytoplasmic for BCRP. P-gp was expressed in 17 of 20 (85%) IMCs compared to 7 of 18 (39%) non-IMCs (P = 0.006). BCRP was expressed within emboli in 15 of 19 (79%) emboli in IMC, 12 of 15 (80%) primary IMCs, and 12 of 18 (67%) non-IMCs, without statistically significant differences (P > .05). All IMCs and 67% of non-IMCs expressed at least 1 of the 2 transporters, and 63% (12/19) of IMCs and 39% (7/18) of non-IMCs expressed both P-gp and BCRP. P-gp and BCRP evaluation might help select patients for chemotherapy. P-gp, expressed in a significantly higher percentage of IMCs vs non-IMCs, might play a specific role in the chemoresistance of IMC.

中文翻译：

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犬炎症性和非炎症性III级乳腺癌中的P-糖蛋白和乳腺癌耐药蛋白。

P-糖蛋白（P-gp / ABCB1）和乳腺癌抗性蛋白（BCRP / ABCG2）的表达通常与肿瘤细胞中的多药抗性（MDR）相关。犬类炎性和III级非炎性乳腺癌（IMC和非IMC）是侵袭性肿瘤，可从化疗中受益。这项研究描述了免疫组化检测未接受化疗的犬中20支IMC和18支非IMC中的P-gp和BCRP。我们的目的是确定P-gp和BCRP的表达是否与“炎症”表型有关，从而为今后研究高度恶性乳腺癌的犬对化疗反应的研究奠定基础。P-gp的免疫标记主要是膜性的，栓子中的标记更为强烈，而BCRP的免疫标记的膜性和细胞质。P-gp在20个IMC中占17个（85％），而在18个非IMC中占7个（39％）（P = 0.006）。BCRP在IMC的19个栓子中有15个（79％）在栓子内表达，在15个（80％）的原IMC中有12个，在18个（67％）非IMC中有12个，无统计学差异（P> 0.05）。所有IMC和67％的非IMC都表达了这两种转运蛋白中的至少一种，并且63％（12/19）的IMC和39％（7/18）的非IMC都表达了P-gp和BCRP。P-gp和BCRP评估可能有助于选择接受化疗的患者。P-gp在IMC中的百分比明显高于非IMC，在IMC的化学耐药性中可能起特定作用。差异无统计学意义（P> .05）。所有IMC和67％的非IMC都表达了这两种转运蛋白中的至少一种，并且63％（12/19）的IMC和39％（7/18）的非IMC都表达了P-gp和BCRP。P-gp和BCRP评估可能有助于选择接受化疗的患者。P-gp在IMC中的百分比明显高于非IMC，在IMC的化学耐药性中可能起特定作用。差异无统计学意义（P> .05）。所有IMC和67％的非IMC都表达了这两种转运蛋白中的至少一种，并且63％（12/19）的IMC和39％（7/18）的非IMC都表达了P-gp和BCRP。P-gp和BCRP评估可能有助于选择接受化疗的患者。P-gp在IMC中的百分比明显高于非IMC，在IMC的化学耐药性中可能起特定作用。