Bio-chemoprevention of recurrenceof superficial bladder cancer-Mechanisms of inhibition by Lactobacillus casei preparation (BLP) on bladder carcinogenesis-

据报道，BLP（口服给药）可预防TUR-Bt后浅表性膀胱癌复发。本研究采用刀豆球蛋白-A凝集法检测了7种乳杆菌对BLP致癌促进作用的抑制作用，并对BLP的致癌促进作用机制进行了初步探讨。包括BLP在内的半数细菌对膀胱癌的发生有抑制作用。研究乳酸杆菌在肠道中的存活能力和其他生物学特性是非常重要的。烟草吸烟是人类膀胱癌发生的主要危险因素，已知烟草吸烟可通过尿液排出致突变物。在我们的初步研究中，BLP明显降低了一些志愿者尿液中的致突变产物（TA 98，S9+），但并非所有志愿者。BLP在肠道内生长，可能由于肠道内微生物菌群的交替而有助于抑制致突变（致癌）物质的代谢。(ex:减少产生亚硝基脲的细菌）。我们已经假设了浅表性膀胱癌复发的两种机制;一种是真正的复发，另一种是第二原发癌。第二原发癌可能起源于膀胱癌患者膀胱上皮中的原始细胞，这些原始细胞在膀胱癌患者膀胱上皮中长期存在，并在某些促进因素的作用下生长成癌。从我们的研究来看，BLP有希望通过减少促进作用来抑制第二原发癌。

It is reported that BLP (p.o.administration) prevents recurrence of superficial bladder cancer after TUR-Bt. In this study, we have investigated mechanisms of the preventive effects of BLP.Seven kinds of lacto-bacilli were tested for its inhibitory ability on carcinogenic promotion using concanavalin-A agglutinating method. Half of bacilli tested including BLP showed the inhibitory effect on bladder carcinogenesis. It is important to investigate the viability in the intestine and other biological characteristics of the lacto-bacilli tested.Tabaco smoking is a major risk factor for bladder carcinogenesis in human, which is known to excrete mutagens in urine. In our preliminary investigation, BLP clearly decreased the mutagenic products in the urine (TA98, S9+) in some volunteers but not in all. BLP which grow in the intestine might contribute to inhibit metabolization of mutagenic (carcinogenic) substances as a result of alternating microflora in intestine. (ex : reducing nitroso-urea producing bacterias).We have hypothesized two mechanisms of recurrence of superficial bladder cancer ; one is true recurrence and the other second primary cancer. The second primary cancer may arise from initiated cells, which persist for long time in the bladder epithelium of the patients with bladder cancer and grow to cancer by some promoting influences. From our investigations, BLP is promising to inhibit the second primary cancer by reducing the promoting influences.