Growth of heterotopic LNCaP prostate cancer tumor in nude mice is not affected by dietary calcium

BACKGROUND. We attempted to provide experimental evidence linking increased dietary calcium to progression of prostate cancer, as suggested by some ep idemiological studies, using a heterotopic prostate cancer nude mice model. METHODS. Twenty heterotopic LNCaP prostate cancer tumor bearing nude mice w ere randomly assigned to one of the four groups: (I) high fat/low calcium d iet, (II) high fat and high calcium diet, (III) high fat diet fortified wit h Vitamin D3, and (IV) high fat and high calcium diet fortified with Vitami n D3. In addition to weekly animal weights and tumor size measurements, the serum prostate specific antigen (PSA), 25-hydroxy Vitamin D3, calcium, pho sphorus, total protein, albumin (to account for bound calcium) [1], and ser um alkaline phosphatase (a measure of bone loss) [2] were determined at the termination of experiments. RESULTS. Although the serum calcium and 25-hydroxy Vitamin D3 were signific antly higher in groups III and IV compared to groups I and II (P < 0.05), t here was no significant difference between the tumor growth rates, final tu mor weights (P = 0.9), and the serum PSA levels (P = 0.94) between the four groups. CONCLUSIONS. The results suggest that dietary calcium does not significantl y affect the growth of heterotopic LNCaP prostate cancer in nude mice. (C) 2001 Wiley-Liss, Inc.