For various types of
tumor therapy, it is suggested that co-targeting of tumor microenvironment, mainly
tumor vasculature, mediates
tumor response mechanisms. Immunohistochemistry for
glucose transporter-1 (GLUT-1),
carbonic anhydrase-IX (CAIX), Ki-67, and
von Willebrand factor VIII for microvessel density (MVD) were performed on
formalin-fixed
paraffin-embedded samples of canine oral
malignant neoplasms. Polarographic
oxygen measurements (median pO2) and perfusion data via contrast-enhanced power Doppler ultrasound (median vascularity, median blood volume) provided additional information. Ninety-two samples were analyzed:
sarcomas (n = 32),
carcinomas (
n = 30), and
malignant melanomas (
n = 30). Polarographic
oxygen and perfusion data was available in 22.8% (
sarcomas n = 9,
carcinomas n = 7,
melanomas n = 5), and 27.1% (
sarcomas n = 10,
carcinomas n = 8,
melanomas n = 7) of cases, respectively. GLUT-1 expression was detected in 46.7% of all samples, and was generally weak. CAIX expression was found in 34.8% of all samples. Median Ki-67 score and MVD count was 19% and 17, respectively. The evaluation of the GLUT-1 score and continuous data showed significantly lower GLUT-1 levels in
sarcomas (mean 5.1%, SD 6.2) versus
carcinomas and
melanomas (mean 16.5%/ 19.0%, SD 17.3/ 20.9, p = 0.001). The expression of CAIX correlated mildly positively with GLUT-1 (p = 0.018, rho = 0.250) as well as with Ki-67 (p = 0.014, rho = 0.295). MVD showed a significantly lower level in
melanomas (mean 12.6, SD 7.7) versus
sarcomas and
carcinomas (mean 21.8/ 26.9, SD 13.0/20.4, p = 0.001). Median vascularity and blood volume were significantly lower in
sarcomas (mean 10.4%, SD 11.0, and mean 6.3%, SD 6.5, respectively) versus
carcinomas (mean 39.2%, SD 16.4 and mean 33.0%, SD 25.6, respectively) and
melanomas (mean 36.0%, SD 18.3, and 31.5%, SD 24.5). Between the 3 histological groups, there was neither a significant difference in the GLUT-1 and CAIX score and continuous data, nor the Ki67 score, or polarographic
oxygen measurements. GLUT-1 continuous data and Ki-67 (p<0.001, rho = 0.403), as well as Ki-67 and MVD (p = 0.029, rho = 0.228) correlated positively and a mild correlation was found between vascularity and GLUT-1 (p = 0.043, rho = 0.408). GLUT-1, CAIX, proliferative index and MVD levels were established as microenvironmental descriptors with the purpose of creating a baseline in order to follow changes seen in the tumor microenvironment after hypofractionated radiation with high doses.