<prompt> The term tumour progression means ?Spread of cancer to distant siteRate of growth of tumourAbility of cancer cells to resemble their normal counterpaSequential appearance of features of increasing malignancy  <response>: Ans. is d i.e., Sequential appearance of features of increasing malignancy o Malignant neoplasm has several characterstics, that are acquired in a stepwise fashion, a phenomenon called tumor progression. o The natural history of most malignant tumors has following four phages ? Malignant change in the target stem cell -- Due to genetic orand environmental factors stem cell is transformed into tumor cell a process is known as transformation and proliferation. Growth and proliferation of transformed cell Local invasion Metastasis 