Carcinogenesis and Cancer Pathology Flashcards
(19 cards)
tumorigenesis
The process by which normal cells transform into cancer cells through multiple genetic and cellular changes.
Self-sufficiency in growth signals, insensitivity to growth-inhibitory signals, evasion of apoptosis, limitless replication, and tissue invasion.
oncogene
A mutated or overexpressed version of a proto-oncogene that promotes uncontrolled cell growth & proliferation.
How do cancer cells achieve growth factor independence?
By prolonging ligand signalling, increasing sensitivity, expressing new receptors, producing their own growth factors, or signalling without ligands.
What is Ras and its role in cancer?
a GTPase that acts like an on/off switch for cell growth; mutations keep it active, driving cancer development.
How do cancer cells become insensitive to growth-inhibitory signals?
By inactivating tumor suppressor genes that control cell division, e.g., loss of Rb function.
tumor suppressor gene
A gene that inhibits cell division or promotes apoptosis; its loss leads to uncontrolled proliferation.
What is the role of Rb in tumorigenesis?
Rb regulates the cell cycle; its loss (e.g., in retinoblastoma, breast, and lung cancers) leads to unchecked cell division.
What does E2F regulate?
It controls the expression of genes essential for DNA synthesis and S-phase entry (e.g., TK, DHFR, DNA polymerase α, cyclins E and A).
p53
a tumor suppressor and transcription factor called the “guardian of the genome”; mutations lead to failed apoptosis and cancer.
How do cancer cells evade apoptosis?
By mutating p53 or other apoptotic regulators, allowing them to survive despite DNA damage or stress.
What is telomerase and its role in cancer?
An enzyme that maintains telomere length, enabling limitless replication in cancer cells.
What is the normal breast tissue organization?
Includes ducts, lobules, epithelial and basal layers, and adipose tissue.
major types of breast cancer
Ductal (80-90%)
ductal carcinoma in situ (DCIS) Non-invasive cancer confined to ducts, usually removed surgically.
invasive ductal carcinoma (IDC) The most common type, accounting for ~80% of all breast cancers.
lobular carcinoma (~10%).
lobular carcinoma in situ (LCIS)
Non-invasive cancer within lobules that hasn’t spread to nearby tissues.
invasive lobular carcinoma (ILC)
A less common invasive breast cancer arising in the lobules.
Name some examples of oncogenes in breast cancer.
HER2, EGFR, Ras, and others involved in tyrosine kinase signaling.
What are some mechanisms by which breast cancer cells acquire GF independence?
prolonged signaling, new receptors, ligand-independent signaling, etc.
What is Triple Negative Breast Cancer (TNBC)?
A breast cancer subtype lacking ER, PR, and HER2; aggressive and linked with BRCA1/2 mutations.
Higher relapse rates, poorer survival, and limited targeted therapies.
clinical signs of breast cancer
Nodularity, thickening, well-defined or diffuse lumps.
stages of breast cancer
range from 0 (in situ) to IV (metastatic).
