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Writing the Abstract
Example of an Abstract Needing Improvement (Basic Science Study) The following abstract could be improved:
Prostate cancer is a leading cause of death in the United States. However, the underlying cause of this disease is poorly understood. Inorganic arsenic is a toxic metalloid long known to be carcinogenic to humans, especially to tissues such as lung, skin, bladder, and liver. Several previously published epidemiologic studies have shown an association between arsenic exposure and prostate cancer. This study was designed to determine whether the nontumorigenic human prostate epithelial cell line RWPE-1 could be malignantly transformed in vitro by arsenite. RWPE-1 cells were derived from normal human prostate epithelium, were immortalized with human papillomavirus 18, and are nontumorigenic. RWPE-1 cells were continuously exposed to 5 µ M arsenite and monitored for signs of transformation, assessed as changes in matrix metalloproteinase-9 levels. For up to 29 weeks, cells were cultured continuously in keratinocyte serum-free medium supplemented with 50 µ g/ml bovine pituitary extract, 5 ng/ml epidermal growth factor, antibiotics, and 5 µ M sodium arsenite. Parallel cultures maintained in arsenite-free medium served as passage-matched controls. Cells were passaged weekly, with new cultures seeded with 1 × 10 6 cells in 75-cm 2 flasks. After 29 weeks of exposure, the arsenite-exposed RWPE-1 cells (referred to as CAsE-PE cells) showed a marked increase in matrix metalloproteinase-9 secretion, a common finding in prostate malignancies. Malignant transformation was confirmed when CAsE-PE cells produced aggressive undifferentiated malignant epithelial tumors in nude mice. Within 10 weeks, 5 of 5 mice inoculated with the CAsE-PE cells developed tumors, whereas none of 5 mice inoculated with the control RWPE-1 cells developed tumors ( P = 0.008). The tumors stained positive for human prostate-specific antigen on histopathologic examination, thus confirming their origin. Thus, our results show that RWPE-1 cells showed a marked increase in matrix metalloproteinase-9 secretion.
Adapted from the well-written abstract in Achanzar WE et al. Inorganic arsenite-induced malignant transformation of human prostate epithelial cells. J Natl Cancer Inst 94:1888–1891, 2002.
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