Review: Control of Precancer Cell Transformation into Cancer Cells: Its Relevance to Cancer Prevention

It is well known that following the action of various carcinogens(chemical, physical, biological) on normal cells, a long period (latency) of several months to years (≈10 months ≈30 years) in humans or one-half to two-thirds of the life span of laboratory animals occurs between development of precancer cells and their transformation into cancer cells. However, the molecular and biological events that take place within the precancer cells during this quiescent stage are not yet fully understood. The main purpose of this review is to evaluate the data from literature as well as my own findings regarding the preneoplastic cells and their progression into neoplastic cells. Recent studies reveal that preneoplastic cell development and transformation into cancer cells is determined initially by genetic(oncogenes, antioncogenes), with sequential multiple somatic mutations, and later by epigenetic or environmental cell factors such as hormones, growth factors (GFs), cytokines, vitamins, and prostaglandins (PGs). These factors can markedly change the evolution of preneoplastic cells by enhancing, retarding, or inhibiting their transformation into cancer cells, or even reversing them to a normal phenotype. These agents act on DNA, RNA, and protein synthesis, as well as on cell replication, cell cycles, cell surfaces, and intercellular communications. DNA, oncogenes, ultrastructural cell surface, and antigenic determination used as biomarkers are essential for early detection of preneoplastic cells and premalignant lesions. Further investigations regarding the precancer cell biology and metabolism will have a paramount significance for designing effective strategies for cancer prevention and treatment.