FINALS LEC: MOLECULAR DETECTION: ONCOLOGY Flashcards
Study of tumors/neoplasm growth of tissue that exceeds and is not coordinated with normal tissue
ONCOLOGY
not recurrent
benign
invasive & tending to recur at multiple sites (cancer)
malignant
movement of tumor cells from the original (primary) site of the tumor to other locations
matastasis
suffix, to the tissue of origin
-Oma
study of cancer at the molecular level
Molecular oncology
An abnormal mass of tissue that usually does not contain cysts/liquid areas
SOLID TUMORS
tumor of epithelial origin
Carcinoma
tumor of bone, cartilage, muscle, blood vessels, or fat
sarcoma
multiple cell types
teratocarcinoma
Abbormal cells in the blood grow out of control
HEMATOLOGICAL MALIGNANCIES
large nos. of WBCs populate the bone marrow & peripheral blood
Leukemia
neoplasm of lymphocytes that form discrete tissue masses
Lymphoma
Plasma cell neoplasms: abnormal plasma cells/cells form tumors in the bones/soft tissues of the body
HEMATOLOGICAL MALIGNANCIES
is caused by nonlethal mutations in DNA affecting 2 types of genes that control the cell division cycle and cell survival
cancer
2 types of genes that control the cell division cycle and cell survival:
Oncogenes
Tumor-supressor genes
● Promote cell division ● Include cell membrane receptors, that are bound by growth factors, hormones, and other extracellular signals
● Support cell survival by inhibiting apoptosis
● >100 in the human genome
Oncogenes
● Factors that control transcription/translation of genes required for cell division
● Participate in repairing DNA damage & in promoting apoptosis
● Slow down/stop cell division by counteracting the movement of the cell from G1-to S (G1 checkpoint) or G2 to M phase (G2 checkpoint)
● >30 in the human genome
Tumor-supressor genes
IN CANCER CELLS
Gain-of-function mutations resulting from:
Amplification/translocation of DNA regions containing the genes
Activating mutations that cause aberrant activity of the proteins
Oncogenes
IN CANCER CELLS
Loss-of-function genes mutations Inactivation of the gene products (deletion, translocation, mutation of the genes)
Tumor-supressor genes
Molecular diagnosis and treatment of cancer cells:
Detection of abnormalities in specific tumor suppressors or oncogenes
ANALYTICAL TARGETS OF MOLECULAR TESTING:
Tissue specific targets
Tumor-specific targets
● Molecular characteristics of the tissue from which a tumor arose
● Detection and monitoring the presence of tumor abnormal amounts or locations of DNA, RNA, proteins or other molecules from these targets
● Examples: DNA/RNA from
1. Cytokeratin genes in gastric cancer 2. Carcinoembryonic antigen in breast cancer
Tissue specific targets
● Genetic structures resulting from mutations in oncogenes & tumorsuppressor genes that are associated with tumor development
● Solid tumors, leukemias, lymphomas ● Mutated cell free nucleic acid/circulating tumor cells can be detected in blood & other body fluids
● Examples: surface receptors, mutated proteins, tumor-associated antigen, metabolic markers
tumor-specific targets
Tyrosine-kinase activity
Normal activity: cell growth and division
Overexpressed in 25%-30% of human breast cancers
Human epidermal growth factor receptor 2, HER/neu/erb-b2 1 (17q21.1)
Detection methods of Human epidermal growth factor receptor 2, HER/neu/erb-b2 1 (17q21.1)
IHC
SOUTHERN, NORTHERN, WESTERN BLOT
FISH
Chromogenic in situ hybridization (CISH)
Silver-enhanced in situ hybridization (SISH)
uses antibodies (fresh/frozen tissues)
IHC
gene amplification increased RNA & proteins
Southern, northern, western blots
direct detection of increased copy nos. of the gene in DNA
FISH