Neoplasm PDF

Neoplasms Cancer Epidemiology New cancer diagnosis = 1,688,000 Cancer deaths = > 600,000 2nd leading cause of death in US Trends in death by cancer types Neoplasia “New growth” Important features Abnormal mass of tissue Uncoordinated Uncontrolled growth (unlike hype...

Neoplasms Cancer Epidemiology New cancer diagnosis = 1,688,000 Cancer deaths = > 600,000 2nd leading cause of death in US Trends in death by cancer types Neoplasia “New growth” Important features Abnormal mass of tissue Uncoordinated Uncontrolled growth (unlike hyperplasia which is controlled) A change has occurred in the cell Tumor = often used for a neoplasm Cancer = often used for a malignant tumor Neoplasms come from normal tissue that can proliferate Neoplasm descriptions Benign or malignant Microscopic appearance Tissue of origin Degree of differentiation Neoplasm nomenclature Benign neoplasms Based on the cell or tissue of origin Parenchyma term + oma Fibroma = from fibroblasts Lipoma = adipose Adenoma = exhibits gland patterns or from glands Chondroma = cartilaginous Leiomyoma = smooth muscle Papilloma = epithelial growth on surface, finger like fronds Neoplasm nomenclature Malignant neoplasm Sarcomas = from mesenchymal tissue (liposarcoma, fibrosarcoma, osteosarcoma) Carcinomas = from epithelial cells Adenocarcinomas = glandular growth Neoplasm nomenclature Some cancers don’t following naming convention Teratoma = made of cells from one than one germ layer Melanoma = melanocytes Hematopoietic = blood cells Benign neoplasms Remain localized Do not invade adjacent tissue Do not metastasize Grow as a cohesive unit Tend to become encapsulated Usually well differentiated Not usually deadly Malignant neoplasm Invade adjacent tissues Metastasize Wide range of differentiation Kill host Biology of neoplasms Differentiation How do the cells resemble normal cells morphologically and functionally Benign are well differentiated Malignant range from differentiated to undifferentiated Anaplasia  Hyperplasia Increase in size but still the correct type of cell  Metaplastia Replacement of one cell type with another Better adapted to altered environment  Dysplasia Disordered growth Loss of uniformity Loss of architectural orientation Do all cells in a tumor have the same ancestor?  Chemicals can cause cancer Carcinogens Mutagens  Cells regulate growth and division Receive growth-stimulatory signals from surrounding Signals processed and integrated with in the cell How do cells transduce signals from outside to inside? Growth factors and receptors Mutated receptors do not require Growth factor signal Most growth factors do not stimulate the cell that made them Cancers acquire the ability of Autocrine signaling How do external signals result in internal changes? -What do these signals do Change in gene expression Protein synthesis increases Induce motility Reorganization of cytoskeleton Provide survival signals  Ras Pathways Mitogen activated protein Kinase pathway  Cell cycle clock G1 = 12-15 hours S = 6-8 hours G2 = 3-5 hours M = 1 hour Checkpoints The R-Point CDKs are cyclic After R point – no external signals needed pRb controls the R-point pRb functions by sequestering TF (E2Fs) p53 is the guardian of the genome p53 can also initiate apoptosis  Retinoblastoma Tumor of precursor of photoreceptors 1 in 20,000 kids -----birth to 8 yo Sporadic----Unilateral Familial----Bilateral Familial form already has one inherited mutation  Transformed characteristics Contact inhibition loss Foci development Altered shape Ability to grow in low serum Immortal Anchorage independence Tumorigenicity  Metastasis 1. Invasion of basement membrane 2. Movement through the ECM 3. Penetrate vascular or lymphatic channels 4. Survival with in the circulating blood or lymph 5. Exit from circulation 6. Survival and growth in new site (could include angiogenesis)  Metastases Origin Melanoma Colon Breast New location Lung Liver Brain