Cell Biological Markers in Breast Tumours: Applications in cyto- and histopathology

Breast cancer is the most common malignant tumour among women in the western world, affecting 8-12 % of the female population. In the Netherlands, breast cancer occurs yearly in IOOO per IOO,OOO women with an absolute incidence of 9,000 new cases per year. The etiology is multifactorial. Age is an important risk factor. The incidence climbs after age 30, followed by a slight dip at menopause and continues to ri se during postmenopausal years. Honnonal influences are weil documented etiological factors: increasing age of the mother at birth of her first child increases the risk of breast cancer whereas late menarche and early menopause decreases the risk. An extensive collaborative study reanalysing 54 epidemiological studies in 25 countries provided evidence for a small increase in the relative risk (1.24) of having breast cancer while taking oral contraceptives and in the IO years after quitting, with no increased risk IO or more years af ter stopping.