CXCR3 chemokine receptor immunoreactivity in primary cutaneous malignant melanoma: correlation with clinicopathological prognostic factors

Background: A role for CXCR3, the receptor for chemokines Mig, IP-10 and interferon-inducible T cell alpha-chemoattractant, in tumour cell migration during melanoma progression has been proposed. Aims: To analyse CXCR3 expression in primary cutaneous malignant melanomas and its comparison with clinicopathological and prognostic factors. Methods: A retrospective immunohistochemical study was carried out on formalin-fixed paraffin-wax-embedded sections from 82 patients with primary invasive cutaneous melanomas, with a monoclonal antibody to CXCR3 (clone 49801.111; R&D Systems). Immunoreactivity was semiquantitatively evaluated: labelling intensity (0, absent; 1, weak; 2, moderate; 3, strong) multiplied by the percentage of cells in each of the four intensity categories. A positive staining was considered when the score was >100. Melanomas were categorised by age, sex, primary site, tumour thickness, growth phase, ulceration, lymphocytic infiltration, recurrence, lymph node and distant metastasis, and survival. Univariate and multivariate statistical analyses were carried out. Results: Of the 82 patients, a positive CXCR3 staining was found in 26 (31.7%) patients, whereas 56 (68.3%) were negative. In univariate analysis, a significant association of CXCR3-positive tumour cell immunostaining with tumour thickness >1 mm (p = 0.003), absence of lymphocytic infiltration (p = 0.04) and the presence of distant metastasis (p = 0.048) was found. Multivariate analysis found tumour thickness as the only independent factor with considerable association with distant metastases. Conclusions: Our findings of a positive correlation of CXCR3 tumour cell immunoreactivity in human primary cutaneous melanoma with tumour thickness >1 mm and absence of intratumoral lymphocytic infiltration support the biological implication of CXCR3 in the tumour progression of cutaneous malignant melanoma.