Overview Acquired abilities of neoplastic tissue apoptotic evasion self-sustained monoclonal growth all cells in a neoplasm are derived from a single progenitor cell can be measured by the presence of single G6PD isoform or Ig heavy and light chain resistance to anti-growth signals angiogenesis must supply nutrients to rapidly growing neoplasm limitless replicative potential invasion metastasis key difference between benign and malignant neoplasms benign remain localized Systemic effects of neoplasia cachexia muscle wasting leading to increased autophagic vacuole formation Steps of neoplastic progression Normal histological characteristics basal to apical differentiation small nucleus:cytoplasm (N:C) ratio intercellular adhesion Hyperplasia histological characteristics increased cell number otherwise normal histology reversible Dysplasia histological characteristics increased cell number loss of cellular orientation increased cell size reversible Carcinoma in situ (preinvasive) histological characteristics increased N:C ratio nuclear changes (chromatin clumping) basement membrane remains intact non-reversible Invasive carcinoma histological characteristics a neoplasm that has breached the basement membrane but is still localized to tissue of origin requirements reduced intercellular adhesions (↓ cadherin) increased attachment to ECM proteins (↑ laminin and integrin receptors) upregulated matrix metalloproteinases to pass through basement membrane non-reversible Metastasis Other Types of Cellular Growth Alterations Metaplasia histological characteristics replacement of 1 adult cell type by another e.g., Barrett's esophagus stratified squamous replaced by simple columnar often a response by a tissue to a change in tissue environment e.g., irritation by smoke, gastric acid, etc. reversible Anaplasia histological characteristics dramatic change in tissue morphology with no resemblance to original tissue most often a malignant neoplasm irreversible Desmoplasia histological characteristics fibrous response to neoplastic growth irreversible