Abstract
The first lecture took up the historical aspects outlined in the opening lecture. In particular, it highlighted the contribution of microscopic tissue analysis to the definition of the different stages of the disease. He also detailed the morphological criteria specific to transformed cells, such as abnormalities of the cell nucleus and chromosomes. I presented evidence of the clonal origin of cancers, which derive from a single cell of origin, even if there is subsequently intratumoral heterogeneity acquired with the evolution of the disease, whether spontaneous or under treatment. The study of the carcinogenic effects of chemicals and radiation on animals has established a direct link between mutagenic and carcinogenic potential. There are, however, chemical carcinogens that are not mutagenic, such as hormones that promote cell growth. Epidemiology has provided a relevant approach to human cancers. In particular, it has shown the importance of aging in the incidence of cancer.
