Cancer #2 cause of death in the United States

  MC CA in women – breast CA

  MC cause of CA-related death in women – lung CA

  MC CA in men – prostate CA

  MC cause of CA-related death in men – lung CA

  PET (positron emission tomography) – used to identify metastases; detects fluorodeoxyglucose molecules

  Cytotoxic T cells need MHC complex to attack tumor

  Natural killer cells can independently attack tumor cells

  Tumor antigens are random unless viral-induced tumor

  Hyperplasia – increased number of cells

  Metaplasia – replacement of one tissue with another (GERD squamous epithelium in esophagus changed to columnar gastric tissue; eg Barrett’s esophagus)

  Dysplasia – altered size, shape, and organization (eg Barrett’s dysplasia)

TUMOR MARKERS

  CEA – colon CA

  AFP – liver CA

  CA 19-9 – pancreatic CA

  CA 125 – ovarian CA

  Beta-HCG – testicular CA, choriocarcinoma

  PSA – prostate CA (thought to be the tumor marker with the highest sensitivity, although specificity is low)

  NSE – small cell lung CA, neuroblastoma

  BRCA I and II – breast CA

  Chromogranin A – carcinoid tumor

  Ret oncogene – thyroid medullary CA

  Half-lives – CEA: 18 days; PSA: 18 days; AFP: 5 days

ONCOGENESIS

  Cancer transformation:

1)  Heritable alteration in genome and;

2)  Loss of growth regulation

  Latency period – time between exposure and formation of clinically detectable tumor

•  Initiation – carcinogen acts with DNA

•  Promotion of cancer cells then occurs

•  Progression of cancer cells to clinically detectable tumor

  Neoplasms can arise from carcinogenesis (eg smoking), viruses (eg EBV), or immunodeficiency (eg HIV)

  Retroviruses contain oncogenes

•  Epstein-Barr virus – associated with Burkitt’s lymphoma (8:14 translocation) and nasopharyngeal CA (c-myc)

  Proto-oncogenes are human genes with malignant potential

RADIATION THERAPY (XRT)

  M phase – most vulnerable stage of cell cycle for XRT

  Most damage done by formation of oxygen radicals → maximal effect with high oxygen levels

  Main target is DNA – oxygen radicals and XRT itself damage DNA and other molecules

  Higher-energy radiation has skin-preserving effect (maximal ionizing potential not reached until deeper structures)

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