Berstein L M, Alexandrov V A
N.N. Petrov Research Institute of Oncology, Leningrad, USSR.
IARC Sci Publ. 1989(96):57-61.
Differences in cancer frequency between men and women are well known. Sexual dimorphism is also observed in the development of some experimental tumours, including those induced transplacentally. Differences in the production and binding of sex hormones by target tissues are evidently not the only cause of sexual dichotomy in the action of modifying factors on transplacental carcinogenesis. In our experiments, the average weight of newborn rats treated with glucose during intrauterine life from day 7 to 20 of gestation exceeded that of control animals, and rats exposed transplacentally to N-methyl-N-nitrosourea (MNU) on day 21 of gestation in combination with glucose (beginning from day 7 of prenatal life to 1.5 months after delivery) had a significantly increased tumour frequency. In males, there was an increased frequency of neoplasms of the nervous system and kidneys, which are typical transplacental carcinogenic effects of MNU; however, in females, neoplasms were induced in other organs and tissues, mainly the mammary gland and pituitary body. Thus, fetal macrosomia acts as a modifying factor in transplacental carcinogenesis also by determining the tumour spectrum in females and males and not only in increasing tumour frequency. The possible causes of these differences and perspectives for further research are discussed.
男性和女性在癌症发病率上的差异是众所周知的。在一些实验性肿瘤的发生过程中也观察到了性二态性，包括经胎盘诱导的肿瘤。靶组织在性激素产生和结合方面的差异显然不是修饰因子对经胎盘致癌作用产生性别差异的唯一原因。在我们的实验中，孕期第7天至20天在子宫内用葡萄糖处理的新生大鼠的平均体重超过了对照动物，孕期第21天经胎盘暴露于N-甲基-N-亚硝基脲（MNU）并同时给予葡萄糖（从产前第7天开始至产后1.5个月）的大鼠肿瘤发生率显著增加。在雄性大鼠中，神经系统和肾脏肿瘤的发生率增加，这是MNU典型的经胎盘致癌作用；然而，在雌性大鼠中，肿瘤发生在其他器官和组织，主要是乳腺和垂体。因此，胎儿巨大症在经胎盘致癌过程中也作为一个修饰因子，不仅增加肿瘤发生率，还决定了雌性和雄性的肿瘤谱。本文讨论了这些差异的可能原因以及进一步研究的方向。
