Neoplasia

Question 1

What three characteristics of neoplasia distinguish it from hyperplasia and repair?

Answer 1

neoplasia is monoclonal, irreversible and unregulated

Question 2

In what two ways can the clonality of a tumor be assessed?

Answer 2

G6PD isoform test - Each person has two isoforms of G6PD but express only one in each cell (the other isoform gets inactivated). A polyclonal tumor will have a 1:1 ratio of each isoform. A monoclonal neoplasm will have only one isoform
Ig light chain test - each B cell either expresses kappa or lambda light chain. Normal and polyclonal ratio is 3:1. Monoclonal neoplasm will have a higher or inverted ratio.

Question 3

What four translocations lead to cancer? What signaling molecule is the translocation associated with? What type of cancer does it cause? Which translocation is associated with the philadelphia chromosome?

Answer 3

t(9:22) - ABL tyrosine kinase; chronic myelogenous leukemia, Philadelphia Chromosome
t(11:14) - Cyclin D on chrom 11 is translocated to the heavy chain Ig on chrom 14; mantle cell lymphoma
t(8:14) - c-MYC on chrom 8 is translocated to the heavy chain Ig on chrom 14; Burkitt lymphoma
t(14:18) - Bcl2 on chrom 18 is translocated to the heavy chain Ig on chrom 14; follicular lymphoma

Question 4

How does the nucleus differ in malignant versus benign tumor cells?

Answer 4

Malignant tumor cells have pleomorphic nuclei that exhibit hyperchromasia and a high nuclear:cytoplasmic ratio
Benign tumor cells have uniform nuclei and a low nuclear:cytoplasmic ratio

Question 5

What immunohistological stains are useful to stain neuroendocrine tumors? melanoma? thyroid follicular cells? muscle tumors? mesenchymal tumors?

Answer 5

neuroendocrine cells - chromogranin
melanoma - S-100
thyroid follicular cells - thyroglobulin
muscle tumors - desmin
mesenchymal tumors - vimentin

Question 6

How is the grading of cancer different from staging of cancer?

Answer 6

grading of cancer - how much does the tumor look like the parent tissue? Degree of differentiation
Staging of cancer (TNM system)- T = tumor size/depth of invasion
N = number of lymph nodes it has spread to
M = metastasis

Question 7

What is the difference between a carcinoma and a sarcoma?

Answer 7

carcinoma is a malignant neoplasm of epithelial tissue. Sarcoma is a malignant neoplasm of mesenchymal tissue (fat, connective tissue, bone, muscle, ect)

Question 8

What are the three routes of metastasis and which cancers are associated with each one?

Answer 8

Hematogenous spread - sarcomas (exceptions: renal cell carcinoma, hepatocellular carcinoma, follicular carcinoma of thyroid, choriocarcinoma)
lymphatic spread - carcinomas
seeding of body cavities - ovarian cancer

Question 9

What are the steps in tumor spread?

Answer 9

1) down regulation of E-cadherin (holds epithelial cells together)
2) attachment to laminin and destruction of basement membrane by collagenase
3) attachment to fibronectin in ECM and local spread
4) entrance into blood vessels or lymphatics