Exam 1; Neoplasia III Flashcards
This is the prototypic anti-apoptosis gene, found in low-grade lymphomas, these tumors grow relatively slowly because the cells do not die quickly - not because they are being stimulated to proliferate
BCL2
Even with multiple genetic abnormalities, tumors cannot exceed what measurements in diameter unless they are vascularized; sustained angiogenesis
1-2mm
Overexertion of BCL2 proteins cells from what
apoptosis, allowing them to survive for prolonged period
Angiogenesis facilities what
metastases; provides access to the vasculature
What are the two 2 major phases of invasion
invasion of the extracellular matrix
vascular dissemination and adhesion/homing of tumor cells
What are the four steps involving the invasion of the ECM
detachment of tumor cells from one another
attachment of tumor cells to matrix components
degradation of ECM
migration of tumor cells
Once in circulation, the tumor cells are vulnerable to what
destruction by the host immune cells
The distribution of tumor metastases can generally be predicted by what
the location of the primary tumor and its vascular or lymphatic drainage
Organ tropism is sometimes seen; for example, lung cancer often spreads to adrenal glands, but almost never involves the skeletal muscle, why?
organ-specific endothelial adhesion molecules bind tumor cell ligands
chemokine receptors on tumor cells home to sites where specific ligands are readily produced
This is critical to the integrity of genome and control of cellular growth; patients with inherited defects in this have an increased cancer risk
DNA repair
This is a familial concert of the color resulting from defective genes involved in DNA mismatch repair and evidence of micro satellite instability (MSI)
hereditary nonpolyposis colon cancer syndrome
This is a defective nucleotide excision repair system; UV light causes pyrimidine cross-linking, halting replication; this puts patients at risk for skin cancer
xeroderma pigmentosum
Bloom syndrome, ataxia telangiectasia and fanconi anemia are characterized by what
hypersensitivty to DNA damage; increasing cancer and other health problems
These genes are involved with the repair of sDNA breaks and may also have tumor suppressor roles; involved in familial breast cancer
BRCA 1 and 2
Every human cancer has shown what
multiple genetic alterations and the loss of two or more cancer suppressor genes
What is meant by tumor progression and heterogeneity
tumors begin as a monoclonal proliferation of one transformed cell, as the daughter cells divide, they tend to develop more and more mutations; by the time the tumor mass has formed, they cells are quite heterogenous and more selected for survival
What is an example of a balanced translocation karyotypic change in the tumor
a translocation between chromosome 22 and 9, resulting in 22 looking shorter
This is the second most prevalent form of karyotypic abnormality in tumors - Rb, colon and oral cancers
deletions
This is form of karyotypic abnormality in tumors such as neuroblastoma and some breast cancers
gene amplifications
What are the three major classes of carcinogenic agents
chemicals
radiant energy
oncogenic virusis
How do some carcinogens react with DNA
directly, but most are indirect and require some metabolic conversion (pro carcinogens) active end products are termed ultimate carcinogens
All chemical carcinogens are what
highly reactive electrophiles, interacting with the electron rich DNA molecule and inducing genetic damage
Some carcinogens can be augmented by what
promoters (agents that have little inherent transforming ability)
The carcinogen is thought to serve as what
the initiator of a mutagenic event, while the promoter drives replication of the damaged cell
