Mortality related to thrombosis in congenital antithrombin III deficiency.

inactivated tumour-suppressor genes This may lead to uncontrolled cell division and rnahgnant transformanon An increasing number of epidemiological studies Support the Fathalla hypothesis Fathalla noted that pregnancy suppresses ovulanon and protects against ovanan cancer The protecnve effect increases with increasing panty Oral contraception inhibits ovulauon and is also associated with decreased nsk of ovanan cancer 4 This reducüon is related to the length of use of oral contraception Furthermore the incidence of ovanan cancer peaks after the menopause and complenon of maximum ovulatory cychcal damage Cruickshank has predicted that because ovulanon occurs more often in the nght ovary, one might txpect ovanan cancer to developmorecommonlyonthenghtside Inastudyofwomenwith epithehal ovanan cancer in Scotland, he found this to be so, with more tumours in the nght ovary than the left In an independent review of nsk factors Pike stated that the major impetus to cell replication is repair of the epithehal surface after ovulanon He noted that each month cells divide to seal the hole and added, "not that cell division itself causes cancer, but whatever does is made worse by cell division" Henderson and Preston-Marnn noted that the division of cells that would usually not be rephcating may be especially error prone because efficient repair mechamsms are absent Epidemiological evidence thus pomts to defecnve cellular repair after ovulanon äs a major nsk factor in ovanan cancer The molecular evidence suggests that this may be attnbutable to inactivated tumour-suppressor genes, possibly the missing link in the Fathalla hypothesis