Luteinizing hormone receptor expression in lymphoma is not affected by body weight, sex, immunophenotype, or tumor stage in gonadectomized dogs

Abstract

Purpose of this investigation was to determine if luteinizing hormone receptor (LHR) expression
in canine lymphoma was affected by body weight, sex, immunophenotype (B cell, T cell) or tumor stage.
Formalin-fixed, paraffin-embedded lymphoma tissue samples from spayed and neutered dogs (n = 40),
representing multiple breeds and mixed breeds, were subjected to routine immunohistochemical
techniques using a polyclonal LHR antibody. Percentage of cells positive for LHR and the staining
intensity (scored 0 - 3) were determined at 400 x magnification. Data were expressed as mean ± standard
deviation and significance was defined as p < 0.05. Differences between sex and tumor phenotype, body
weight and tumor stage were compared. All tumor samples had cells positive for LHR. However,
percentage of cells expressing LHR and its immunostaining intensity varied among individuals. There
were no significant differences in percentage of LHR positive cells or staining intensity within sex or
immunophenotype. Additionally, there was no significant association between percentage of LHR
positive cells or staining intensity within body weight or tumor stage. We concluded that increased risk of
lymphoma in spayed and neutered dogs was not related to body weight, sex, immunophenotype or tumor
stage. However, it is possible that risk of lymphoma may be related to increased LHR activation
following gonadectomy.