class 2 (ch9; clinical manifestations of cancer) Flashcards
what is cancer?
cancer is a collection of more than 100 diffferent diseases, each caused by a specific and often unique accumulation of genetic and epigenetic alterations
what is a tumor?
any swelling caused by inflammation, but now used to describe a new growth (Neoplasm)
what are the two type of cancer?
Malignant or benign
what are benign tumors?
well-differenciated cells and well organized stroma; surrounding capsule fo the CT
what is a malignant tumor?
have more rapid growth rates and specific microscopic alterations, including loss of differentiation and absence of normal tissue organization. often have large darkly stained nuceli and mitotic cells are common
anaplasia
loss of cellular differentiation
pleomorphic
marked variability of size and shape
metastasis
the ability ot spread; very dangerous in cancer cells
carcinomas
cancer cells arising in the epithelial tissue
Carcinoma in situ (CIS)
early stage growths are localized to the epitheium but have not penetrated the local basement membrane or invaded the surrounding stroma.
where are CIS found?
cervix, skin, oral cavity, esophagus, and bronchus.
how do we classify tumors?
immunohistochemical analysis and protein expression
tumor markers?
substances produced by both benign and malignant cells that are either present in or on tumor cells or found in blood, spinal fluid, or urine.
paraneoplastic syndrome
if the tumor marker itself has biologic activity, then it could cause symptoms.
what does it mean when tumor markers are elevated?
ones that are high early in the course of common cancers remains a high priority beause the early detection of cancer often improves the Tx outcome.
what are transformed cells?
cancer cells are described as transformed cells because they can be created from normal cells. (often have markedly decreased requirments for external growth factors).
what is contact inhibition?
unlike normal cells cancers cells lack this and continue to crowd; eventually piling up on eachother.
anchorage dependednt?
cancer cells continue to divide even when they are suspended in a soft agar gel. ( normal cells usually dont grow unless they are attached to something).
what is the epidemilogic date about cancer?
each individual acquires a number of genetic “hits” or mutations over time. four-seven genetic hits are required over time for full blown cancer to occur.
what is clonal proliferation?
progency can accumulate faster than nonmutent neighbors.
what are oncogenes?
mutant genes that in their normal nonmutant state direct synthesis of proteins that positively regulate (accelerate) proliferation.
tumor-supressor genes?
encode proteins that in their normal state negatively regulate proliferation. prevent cell mutation.
what are the three types of DNA changes?
small DNA changes, large DNA changes, and epigenetic changes.
what are point mutations?
small scale changes in DNA, the alteration of one or a few nucleotide base pairs.
what are chromosome translocations?
they are large changes in chromosome structure in which a piece of one chromosome is translocated to another chromosome.
what is copy number variation?
larger regions of DNA encompassing entire genes can be gained or lost. (during cancer it may amplify oncogenes or delete tumor supressor genes).
what is gene amplification?
a type of chromosome structural abnormality bthat can activate oncogenes. they are the result of duplication of a region of a chromosome over and over again so that there may even be hundreds of copies present.
retinoblastome (RB) gene?
one of the first discovered tumor supressor genes, normally strongly inhibits the cell division cycle.
what is inactivated and activated in cancer?
oncogenes are activated and tumor suppressor genes are inactivated. (it takes 2 hits to inactivate).
what is loss of heterozygosity?
for the fucntion of a tumor supressor to be lsot, both chromosomal copies (alleles) of the genes must be inactivated. so by just losing one you have LOH
what is epigenetic silencing?
caused by reversible chemical modification (methyalon or acetylation) of histones and related chromatin components.
what happens during epigenetic silencing?
whole regions fo chromosomes are normally shut off by silencing, so that the pattern of gene expression is different than that seen in other cells with the same genes.
