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Oncology Basic Science 12/1/09. Incidence  1.44 million new cancer cases were diagnosed in the United States last year.  Also, over one million cases.

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Presentation on theme: "Oncology Basic Science 12/1/09. Incidence  1.44 million new cancer cases were diagnosed in the United States last year.  Also, over one million cases."— Presentation transcript:

1 Oncology Basic Science 12/1/09

2 Incidence  1.44 million new cancer cases were diagnosed in the United States last year.  Also, over one million cases of basal and squamous cell carcinomas of the skin  #2 cause of death in U.S.

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4 Hallmarks of Cancer  Hallmarks of Cancer

5 Tumorigenesis  initiation –Initiating events such as gain of function of oncogenes  promotion –loss of function of tumor-suppressor genes may lead a single cell to acquire a distinct growth advantage  progression –disease of clonal progression as tumors arise from a single cell and accumulate mutations that confer on the tumor an increasingly aggressive behavior. –Most tumors go through a progression from benign lesions to in situ tumors to invasive cancers –Mutations in at least four or five genes are required for formation of a malignant tumor, whereas fewer changes suffice for formation of a benign tumor

6 Oncogenes  Designated by three-letter abbreviations, such as myc or ras.  Oncogenes are further designated by the prefix "v- " for virus or "c-" for cell or chromosome, corresponding to the origin of the oncogene when it was first detected.  Oncogenes may be –growth factors - platelet-derived growth factor –growth factor receptors - HER2 –intracellular signal transduction molecules - ras –nuclear transcription factors - c-myc

7 Oncogenes  ras (k-ras) –G Protein defect –Colon cancer, pancreatic cancer  ret – medullary CA of thyroid  erb B –epidermal growth factor receptor –Breast cancer  myc (c-myc, n-myc, l-myc) –Transcription factors –Burkitt’s lymphoma, nasopharyngeal CA  c-kit – CML, Gastric leiomyoma (GIST)  src- tyrosine kinase defect  sis- PDGF receptor

8 Tumor Suppressor Genes Retinoblastoma(RB1) Chromo 13 Cell cycle RetinoblastomaOsteosarcoma P53 Chromo 17 Cell cycle Li-Fraumani- sarcoma, breast, leukemia adrenal, brain APC Chromo 5 Cell adhesion FAP (colon cancer) DCC Chromo 18 Cell adhesion Colon cancer bclApoptosis Breast CA, multiple BRCA I/II Chromo17/13 DNA repair Breast CA

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10 Ghetto C3PO

11 Cancer Invasion  in situ cancer vs invasive cancer - tumors that breach the basement membrane –glycoproteins of the ECM bind to tumor cell integrin receptors –Serine, cysteine, and aspartic proteinases and MMPs  MMPs comprise a family of metal-dependent endopeptidases  Active in alsmost every cancer type

12 Metastasis

13 Metastasis  Metastasis is an inefficient process  Must establish vascularization to sustain the new tumor  Only a small subset of cancer cells is able to initiate micrometastases, even smaller - macrometastases.

14 Metastasis  Colon  Liver  Melanoma  Skin, Lung, Small bowel  Lung  Brain, Heart  Sarcoma  Lung  Breast  Brain, Adrenal  To Bone  Breast, Prostate, Thyroid  To Skin  Breast, melanoma  To Ovary  Stomach (Krukenberg)  To Small bowel  Melanoma

15 Evil Nodes  Supraclavicular node –Stomach (Virchow’s Node) –Neck, breast, lung, pancreas CA  Axillary Node –Lymphoma #1 –breast, melanoma  Periumbilical node –pancreas (Sister Mary Joseph)

16 Selected Genes/Cancers  Hereditary Retinoblastoma (Rb1) –led to the theory that a single mutation is not sufficient for tumorigenesis. –hereditary retinoblastoma involves two mutations, of which one is germline and one somatic, whereas nonhereditary retinoblastoma is due to two somatic mutations –Knudson's "two-hit" hypothesis. –A "hit" may be a point mutation, a chromosomal deletion referred to as allelic loss, or a loss of heterozygosity, or silencing of an existing gene.

17 BRCA1, BRCA2  Of women with early-onset breast cancer (aged 40 years or younger), nearly 10% have a germline mutation in BRCA1 or BRCA2.  Higher in patients such as in the Ashkenazi Jewish population.  Cumulative risks of developing breast cancer and ovarian cancer –BRCA 1– 87% and 44% –BRCA 2- 84% and 27%  Responsible for male breast CA

18 APC Gene and Familial Adenomatous Polyposis  Hundreds to thousands of polyps in the colon and rectum.  Appear in adolescence progress to colorectal cancer.  FAP is associated with benign extracolonic manifestations –congenital hypertrophy –retinal pigment epithelium –epidermoid cysts, and osteomas.  Also at risk for –upper intestinal neoplasms (gastric and duodenal polyps, duodenal and periampullary cancer), –hepatobiliary tumors (hepatoblastoma, pancreatic cancer, and cholangiocarcinoma), –thyroid carcinomas, desmoid tumors, and medulloblastomas.  Gardner’s and Turcot’s

19 Mismatch Repair Genes and Hereditary Nonpolyposis Colorectal Cancer (HNPCC)  Autosomal dominant hereditary cancer syndrome that predisposes to a wide spectrum of cancers, including colorectal cancer without polyposis.  DNA mismatch repair genes  HNPCC consists of at least two syndromes: –Lynch syndrome 1- colorectal cancer –Lynch syndrome 2- colorectal cancer + carcinoma of the endometrium, transitional cell carcinoma of the ureter and renal pelvis, and carcinomas of the stomach, small bowel, ovary, and pancreas.  Amsterdam Criteria

20 Amsterdam Criteria (3-2-1 rule)  At least 3 relatives with an HNPCC-associated cancer: colorectal cancer, or cancer of the endometrium, small intestine, ureter or renal pelvis.  At least two successive generations should be affected  At least one tumor should be diagnosed <50 years of age

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23 Carcinogens  Coal Tar – larynx, skin, bronchial CA  Beta-naphthylamine – bladder CA  Benzene- leukemia  Asbestos – Mesothelioma  Chinese-style salted fish- Nasopharyngeal carcinoma

24 Carcinogens  Epstein-Barr virus- –Burkitt's lymphoma –Burkitt's lymphoma –Hodgkin's disease –Hodgkin's disease –Nasopharyngeal carcinoma  Hepatitis B/C virus- Hepatocellular carcinoma  HIV –Kaposi's sarcoma –lymphoma  Human papillomavirus 16 and 18 –Cervical cancer –Anal cancer

25 Screening  x?aID=

26 Cancer Diagnosis  Fine-needle aspiration –is easy and relatively safe –disadvantage of not giving information on tissue architecture. Cannot differentiate between an invasive and noninvasive tumor  Core-needle biopsy –is more advantageous when the histologic findings will affect the recommended therapy. –performed either by direct palpation or can be guided by an imaging study –disadvantage of introducing sampling error  Open biopsies –have the advantage of providing more tissue for histologic evaluation and the disadvantage of being an operative procedure.  Incisional biopsies are reserved for very large lesions in which a definitive diagnosis cannot be made by needle biopsy.  Excisional biopsies are performed for lesions for which either core biopsy is not possible or the results are nondiagnostic. Should be performed with curative intent.

27 Staging  TNM staging  For Absite, review: –Breast Cancer –Colon Cancer –Melanoma –Lung cancer

28 Tumor Markers MarkerCancerSensitivitySpecificity Prostate-specific antigen (PSA) Prostate57–9355–68 Carcinoembryonic antigen (CEA) Colorectal40–4790 Alpha-fetoprotein (AFP)Hepatocellular9865 Cancer antigen 19-9Pancreatic78–9095 Cancer antigen 125Ovarian Beta-HCGTesticular, Choriocarcinoma NSESmall cell lung Neuroblastoma

29 Prostate-Specific Antigen  PSA is the best serum marker available with highest sensitivity  PSA levels may be elevated in benign prostate conditions such as prostatitis and benign prostatic hyperplasia, as well as in men with prostate cancer.  useful in evaluating treatment and monitoring for recurrence after therapy. In monitoring for recurrence, a trend of increasing levels is more significant than a single absolute elevated value.  American Urologic Association and the American Cancer Society both recommend yearly PSA testing for men aged 50 years and older  total serum PSA level of 4 ng/mL should be used as a threshold for performing a prostate biopsy

30 Surgical Management of Primary Tumors  The goal of surgical therapy for cancer is to achieve oncologic cure.  A curative operation presupposes that the tumor is confined to the organ of origin  Patients in whom the primary tumor is not resectable with negative surgical margins are considered to have inoperable disease. –The operability of primary tumors is best determined with imaging studies that can define the extent of local-regional disease.  Primary tumors can be resected for palliative reasons, such as improving the quality of life by alleviating pain, infection, or bleeding.

31 Surgical Management of Lymph Nodes  Unlike most carcinomas, soft tissue sarcomas rarely metastasize to the lymph nodes (<5%); therefore lymph node surgery usually is not necessary.  generally accepted that a formal lymphadenectomy is likely to minimize the risk of regional recurrence of most cancers  On the other hand, there have been opposing opposing views regarding the role of lymphadenectomy in survival of cancer patients.

32 Surgical Management of Lymph Nodes  Relatively new development  Lymphatic mapping and sentinel lymph node biopsy were first reported in 1977 by Cabanas for penile cancer  Lymphatic mapping –isosulfan blue dye, technetium-labeled sulfur colloid or albumin, or a combination of both techniques to detect sentinel nodes.  ***There is no role for sentinel LN BX for clinically palpable nodes

33 Surgical Management of Distant Metastases  depends on the number and sites of metastases, the cancer type, the rate of tumor growth  such therapy has resulted in cure in selected cases with isolated metastases to the liver, lung, or brain. 25% 5 year survival for a single colonic met to liver if successfully resected.

34 Chemotherapy  Classified according to the phase of the cell cycle during which they are effective. –Cell-cycle phase–nonspecific agents have a linear dose-response curve, such that the fraction of cells killed increases with the dose of the drug. –Cell-cycle phase–specific drugs have a plateau, and cell kill will not increase with further increases in drug dose  Methotrexate and 5-FU are cell cycle specific, all others are non-specific

35 DrugMech of actionSide FX MethotrexateInhibits dihydrofolate reductase inhibiting purine synthesis Renal toxicity 5-Flourouracil (5-FU) Inhibits thymidylate synthesis inhibiting purine synthesis CyclophosphamideAlkylating agentGonad dysfxn, SIADH, hemorrhagic cystitis IsofosfamideAlkylating agent BisulfanAlkylating agentPulmonary fibrosis CisplatinPlatinum alkylating agentNephro, neuro, ototoxic CarboplatinPlatinum alkylating agentBone marrow surpression VincristineMicrotubule inhibitorNeurotoxic VinblastineMicrotubule inhibitorBone marrow surpression TaxolMicrotubule stabilizer EtopsideInhibits topoisomerase BleomycinAntitumor antibioticPulmonary fibrosis DoxorubicinAntitumor antibiotic (O2 radical formation) Heart toxicitiy LevamisoleAntihelminthic drug, stimulates immune system

36 Radiation Therapy  M phase is most vunerable stage of cell cycle for XRT  Most damage to DNA is done by formation of oxygen radicals with H2O2 intermediate –More oxygenated tumor = more damage –Large tumors less responsive  To a lesser extent, ionizing radiation itself can cause direct DNA damage  Most is external beam radiation  Brachytherapy: source of radiation delivered directory into operative bed using catheters. Allows high concentrated radiation with fewer side effects.

37 Radiation Therapy  Fractional Doses –Allows repair of normal cells –Allows reoxygenation of tumor –Allows redistribution of tumor cells in cell cycle  Radiosensitive tumors: –Seminomas, lymphomas  Radioresistant tumors –Epithelial, Sarcomas

38 Side effects

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40 THE END


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