الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Breast cancer is the most common malignancy among women in most developed and developing regions of the world. The most common histological type is infiltrating ductal carcinoma which comprises about 70 to 80 % of all breast cancer types.
Mammogram screening reduces breast cancer mortality through earlier diagnosis, which is why it should be done to all women at risk of breast cancer. The most important risk factors are old age, early menarche, late menopause, nulliparous, women with increased endogenous hormones (like estrogen and prolactin), administration of exogenous hormones (as used in hormone replacement therapy and oral contraceptive pills), previous benign breast disease and positive family history for breast cancer specially in first degree relative.
Vitamin D is a fat-soluble vitamin that exists in a few kinds of food and is mainly synthesized by the skin through sun exposure from 7-dehydrocholesterol. After absorption or synthesis, vitamin D is converted into 25(OH)D in the liver, which is the major storage form of vitamin D. The plasma 25(OH)D level has been widely recognized as the indicator of vitamin D status for the human body due to its long serum half-life (2-3 weeks). In the kidney, 25(OH)D is hydroxylated by mitochondrial 1α-hydroxylase to yield 1α,25-(OH)2D, the active form for vitamin D. In the cells, the molecule 1α,25-(OH)2D binds to the vitamin D receptor (VDR), a member of steroid hormone receptor family which exerts transcriptional activation or repression of target genes activity through interaction with other co-factors.
Although the most important and known function of vitamin D is Ca2+ transport and bone mineralization in the human body, it has been well established that 1α,25(OH)2D3, or vitamin D analogues might have potential as anticancer agents through antiproliferative effects, promoting cellular differentiation, activating apoptotic pathways and inhibiting angiogenesis. Vitamin D insufficiency could have an etiological role in various human cancers as several studies found that vitamin D could be incriminated in the risk of cancer while others see it as a prognostic factor for cancer patients.
The present study aimed at measuring 25 hydroxycholecalciferol levels in newly diagnosed breast cancer females using High Performance Liquid Chromatography (HPLC) technique. Sixty subjects were recruited in this study; thirty newly diagnosed breast cancer patients (group I) admitted to oncology department in Alexandria main university hospital in the period from November 2012 to October 2013 and thirty apparently healthy volunteers as a control group (group II).