[Morphological and biological features of neoplasms: Integration of molecular findings]

Integration of morphologic and molecular findings in neoplasms (for details, please refer to Histopathology 2008; 53(1):1-19). Molecular definition of neoplasm and precursor lesions. Intraepithelial lesions and topographic heterogeneity. Biological bases of neoplasm natural history. - Clonality and loss of heterozygosity (LOH) in neoplasms. Fractional allelic loss. - Genetic control of initiation and promotion. Tumor progression. - Topographic heterogeneity and tumor cell segregation. Accumulation of genetic alterations. - Molecular pathways pleiotropism and redundancy.