The expression of CXCR4, analyzed by immunohistochemistry, was observed in 29 out of 31 (93%) of primary carcinoma samples (from a total of 24 queens) although the staining pattern and intensity differed between tumors as evaluated by CXCR4 scores (1+, 2+ and 3+) reported in Table 1. This evidence concerns the gene CXCR4 and carcinoma.