Which appears to be the dominant risk factor category for neoplastic development, genetics or environmental factors?
Do mixed tumors (pleomorphic adenomas) have cells from multiple germ layers?
No, they often have epithelial and myoepithelial cells (both from the same layer and clonal start)
What is a choristoma?
A nonneoplastic nodule of well-developed tissue in the wrong place (a heterotopic rest of cells)
What is a morphologic hallmark of malignancy?
What are some signs of a lack of differentiation in malignant cells (anaplasia)?
Pleomorphism, abnormal nuclear morphology, mitoses, loss of polarity, central areas of ischemic necrosis, loss of function
What are the two most major characteristic behaviors of a malignancy?
Metastasis; local invasiveness
Do tumors have their own contained functional lymphatics?
No, the ones around the periphery of the tumor are sufficient
Is it accurate to say that carcinomas spread via lymphatics and sarcomas spread via hematogenous routes?
Yes, but it is misleading as the lymphatics and vascular systems are very interconnected.
What are two major spots of dissemination in hematogenous spread?
The liver and lungs
What tumors are very likely to spread to the vertebral column?
Proximal tumors (e.g. the thyroid and prostate) metastasize through the paravertebral plexus
What tumor has a high affinity for venous invasion and invades the branches of the renal vein and then the renal vein itself?
Renal cell carcinoma (it can even reach all the way up the inferior vena cava to the heart)
To where do breast cancers preferentially spread?
To where do bronchogenic carcinomas preferentially spread?
The adrenals and the brain
To where do neuroblastomas preferentially spread?
The liver and bones
What are the most common cancers in men?
Prostate, lung, and colon/rectum
What are the most common cancers in women?
Breast, lung, and colon/rectum
What four cancers account for more than 50% of cancer diagnoses and deaths in the U.S.?
Lung, female breast, prostate, an colon/rectum
What are the most common cancers in the world?
Lung, stomach, and liver in men; breast, cervix, and lung in women
What percentage of cancers worldwide are thought to be directly or indirectly caused by infectious agents?
What is the single most important environmental factor contributing to premature death in the U.S.?
What percentage of lung cancer deaths can be attributed to smoking?
What are some acquired conditions that can predispose to cancer (3)?
Chronic inflammation, precursor leisons, immunodeficiency states
What are the four classes of normal regulatory genes that are the principal targets of cancer-causing mutations?
Proto-oncogenes, tumor suppressor genes, apoptosis-regulating genes, and genes involved in DNA repair
What are the mutations called that contribute to the development of a malignant phenotype?
What are the three steps of tumor development?
Initiation, promotion, and progression
What is the Warburg effect?
Tumors switch to aerobic glycolysis from oxidative phosphorylation. Aerobic glycolysis provides rapidly dividing tumor cells with metabolic intermediates that are needed for the synthesis of cellular components, whereas mitochondrial oxidative phosphorylation does not
What is a particularly important proto-oncogene?
The signal transducer RAS (as well as MYC, P13K, BRAF, ERBB1 and 2)
What are the three RAS mutations in humans?
HRAS, KRAS, NRAS
What is the Philadelphia chromosome?
CML change; BCR-ABL kinase mashup between chromosomes 9 and 22
What two genes promote G1/S progression? What two genes inhibit it?
D cyclin genes, CDK4; RB, TP53