CHAPTER 8
Surgical Oncology
Test Taking Tips
• Oncology questions can be quick points on the ABSITE, especially in the basic science portion of the exam.
• Carcinoids and GISTs are hot topics.
CELL CYCLE
FIGURE 8-1. The cell cycle. The ability to recognize microscopically cells during both mitosis and DNA replication (by autoradiography after administering radiolabeled thymidine) led to the concept of the cell “cycle.” In this concept new interphase cells undergo a period after leaving mitosis and before starting DNA synthesis called the first gap or G1. Another gap, G2, occurs after DNA replication and before the next mitotic prophase. After mitosis both new cells repeat this cycle. In rapidly dividing cells, G1 is a period in which cells accumulate the enzymes and nucleotides required for DNA replication, S is the period devoted primarily to DNA replication, G2 is a usually short period of preparation for mitosis, and M includes all phases of mitosis itself. In rapidly growing human tissues the cell cycle varies from 24 to 36 hours. The length of G1 depends on many factors and is usually the longest and most variable period; the length of S is largely a function of the genome size. G2 and mitosis together normally last only 2 to 3 hours. (Reproduced from Mescher A. Junqueira’s Basic Histology: Text and Atlas. 12th ed. www.accessmedicine.com Copyright © The McGraw-Hill Companies, Inc. All rights reserved.)
In what phase of mitosis does the nucleus disappear?
Prophase
In what phase of mitosis does chromosome alignment occur?
Metaphase
In what phase of mitosis do chromosomes separate?
Anaphase
In what phase of mitosis do nuclei form around replicated DNA?
Telophase
Name the purines:
Guanine, adenine
Name the pyrimidines:
Cytosine, thymidine, uracil
What is translation as it refers to the cell cycle?
Protein synthesis using an mRNA template by ribosomes
What is transcription as it refers to the cell cycle?
Synthesis of mRNA from DNA template by RNA polymerase
In what phase of the cell cycle do protein synthesis and chromosomal duplication occur?
S phase
In what phase of the cell cycle does mitosis occur?
M phase
TUMOR MARKERS
What tumor marker is associated with choriocarcinoma/testicular cancer?
β-Human chorionic gonadotropin (HCG)
What tumor marker is associated with colon cancer?
Carcinoembryonic antigen
What tumor marker is associated with liver cancer?
α-Fetoprotein
What tumor marker is associated with ovarian cancer?
CA-125
What tumor marker is associated with pancreatic cancer?
CA 19-9
What tumor marker is associated with melanoma?
S-100
Chromogranin A is elevated in what adrenal tumor?
Carcinoid tumor
What tumor marker is associated with prostate cancer?
Prostate-specific antigen (PSA)
Table 8-1 Genes Associated with Hereditary Cancer
What tumor marker is associated with neuroblastoma/small cell lung CA?
Neuron-specific enolase
What tumor marker is associated with nonseminomatous testicular cancer?
α-Fetoprotein
CARCINOGENESIS
What is the term for an increased number of cells?
Hyperplasia
What is the term for replacement of one tissue with another?
Metaplasia
What is the term for altered shape, size, or organization of cells?
Dysplasia
What is the most sensitive stage of the cell cycle for radiation?
M phase
What is the term for human genes with malignant potential?
Proto-oncogenes
What cancer are aflatoxins associated with?
Hepatocellular carcinoma
What organism produces aflatoxins?
Aspergillus flavus
What cancer is associated with Schistosoma haematobium?
Urinary bladder cancer
What cancer is associated with Opisthorchis viverrini?
Cholangiocarcinoma
What cancer was associated with chimney sweeps (due to soot)?
Scrotal cancer
What cancer is associated with benzene?
Leukemia
What is the primary cause of skin cancer in humans?
Ultraviolet radiation
How do viruses cause cancer?
Insertion of foreign DNA into the human genome
What is the first phase of chemical carcinogenesis?
Initiation. A carcinogen reacts with DNA irreversibly without enzymatic activity or specificity
What is the second phase in chemical carcinogenesis?
Promotion. Cells that were initiated are then stimulated to develop into cancer cells. This process is slow and reversible
What is the last phase of chemical carcinogenesis?
Progression. This involves the maturation of cancer cells
What cancers are associated with the Epstein-Barr virus?
Nasopharyngeal carcinoma and Burkitt lymphoma
What viruses are associated with adult T-cell leukemia?
Human immunodeficiency virus and human T-lymphotropic virus type 1
What is the major fuel source for tumor cells?
Glutamine
What are small circular rings of DNA capable of autonomous replication?
Plasmids
BREAST CANCER
What hormone receptors are commonly tested for in breast cancer?
Estrogen receptor and progesterone receptor
What hormonal therapy is used for estrogen- and progesterone receptor–positive breast tumors?
Hormone receptor–positive tumors are targeted by tamoxifen and aromatase inhibitors. Tamoxifen has shown survival benefit as adjuvant treatment and for metastatic disease in both premenopausal and postmenopausal women. Aromatase inhibitors (anastrozole, letrozole, and exemestane) have shown a survival benefit as adjuvant therapy and for metastatic disease in postmenopausal women.
What cancers are associated with estrogen replacement therapy?
Endometrial and breast
What is the mechanism of action of Tamoxifen?
Selective estrogen receptor modulator, which binds to and inhibits estrogen receptors
What tumor markers are associated with breast cancer?
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