KIF3B protein expression loss correlates with metastatic ability of prostate cancer

摘要

Kinesin family member 3B (KIF3B) is a microtubule motor kinesin involved in mitotic progression and vasculotropism. A novel therapeutic target, it is overexpressed in several cancers [PMID 29904055]. Its significance in prostate cancer (PC) was uncertain. Methods: 89 cases, including tissue microarrays from 70 prostatectomies comprising matched cancer and benign spots, 19 additional prostatectomy tissues, plus 16 prostate cancer metastases (7 nodal and 9 distant sites; 8 had matched primary PC) were stained with rabbit polyclonal KIF3B antibody. Cytoplasmic immunoreactivity was scored: 0 (negative) to 3+ (strong and diffuse). 39 patients had no nodal metastases, 31 had positive lymph nodes, and 19 had nodes not sampled. Gleason grade groups were 1 (9), 2 (28), 3 (39), 4 (1), and 5 (12). 15 cases had cribriform pattern. AJCC stages were 2 (48), 3 (29), unknown (12). Results: KIF3B in PC (mean 1.0) was higher than in benign prostate (mean 0.1, P0) expression compared to cases without metastases or with unsampled lymph nodes (P0.01, chi-square test). Reactivity of paired metastatic tissue and primary PC correlated strongly (Pearson coefficient: +0.7). No significant trends were found by grade group, cribriform status, or stage. Conclusions: KIF3B is a PC marker. Metastatic cancers showed less KIF3B expression than their primary PC counterparts, and primary cases with positive nodes demonstrated reduced positivity, suggesting use as a prognostic marker. It is possible that KIF3B protein becomes altered prior to metastases, preventing immunohistochemical detection.