Fallopian adenocarcinoma is a rare malignancy arising in the epithelium of the fallopian tube. Fallopian tube epithelium has been proposed as a tissue origin for high-grade serous ovarian carcinoma, the deadliest gynecologic malignancy. Given the commonalities in dissemination and treatment of these malignancies, we contemplated the possibility of similar patterns of gene expression underlying their progression. To reveal potential similarities or differences in the gene expression of fallopian adenocarcinoma and high-grade serous ovarian carcinoma, we tested expression of the fractalkine receptor (CX₃CR1) and its ligand, fractalkine (CX₃CL1), in the specimens of normal and pathologic fallopian tube using immunohistochemistry. Our data show that CX₃CR1 is expressed in the normal, cancer adjacent normal, inflammatory, and malignant fallopian epithelium. CX₃CL1 was expressed only by the normal and cancer adjacent normal fallopian tube epithelium; its expression was largely lost in the inflammatory and malignant fallopian epithelium. In opposite, both CX₃CR1 and CX₃CL1 are expressed in high-grade serous ovarian carcinoma. These findings are consistent with an idea that fallopian adenocarcinoma and high-grade serous ovarian carcinoma, although currently thought to arise from the same organ, may not share similar molecular characteristics. Full article