lab diagnosis of cancer- KEVIN RICHARD.pdf

lab diagnosis of cancer- KEVIN RICHARD.pdf

• 1.
  LABORATORY DIAGNOSIS OFCANCER KEVIN RICHARD SHORT NOTE *
• 2.
  LABORATORY DIAGNOSIS OFCANCER • HISTOPATHOLOGY • CYTOLOGY • IMMUNOHISTOCHEMISTRY • MOLECULAR AND CYTOGENETIC DIAGNOSIS • FLOW CYTOMETRY • TUMOUR MARKERS • ELECTRON MICROSCOPY
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  HISTOPATHOLOGICAL EXAMINATION Clinical data:It should be provided for accurate diagnosis. Examples: – Radiation causes changes in the skin or mucosa mimic changes seen in cancer. – Sections taken from the site of a healing fracture can mimic an osteosarcoma. • Adequate and representative area of the specimen should be sent. • Proper fi xation.
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  Frozen Section - Inthis method, tissue is frozen and sections are cut by special instrument called freezing microtome or cryostat. • Its uses are: 1. Rapid diagnosis and useful for determining the nature of a tumor (benign or malignant) lesion, especially when the patient is still on the operation table. 2. Needle biopsy 3. Endoscopy biopsy 4. Incision biopsy 5. Excision biopsy
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  CYTOLOGICAL EXAMINATION Study ofIndividual cells - Fine Needle Aspiration Cytology : Direct & Image guided - Exfoliative cytology - Abrasive cytology FNAC PROCEDURE - Push the needle into the lesion (lymph nodes , swelling in salivary glands , breast , bone or soft tissue lesions )—apply suction— move the needle rack and forth in the lesion — withdraw the syringe — remove the needle and draw air into the syringe— deposit the aspirate on microscopic slide. Ideal aspirate- creamy consistency with high cell and low fl uid content Stain - PAPANICOLAOU STAIN ! ADVANTAGES- Rapid diagnosis , cheaper, simple technique and high diagonostic accuracy. DISADVANTAGES- may cause complications like bleeding, infection.
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  EXOLIATIVE CYTOLOGY study ofspontaneously exfoliated (shed) cells from the lining of an organ into a body cavity. • Sources of exfoliated cells: – Surface of mucosal or epithelial lining: Cells may be shed naturally or obtained by arti fi cial exfoliation. ◆Female genital tract/ Respiratory tract/ GI tract ◆ Urinary tract: Voided urine. – Body fl uids: Usually cells are shed naturally into body fl uids. ◆ E ff usions: Pleural, peritoneal, pericardial or Other fl uids: Synovial fl uid, CSF and semen. Fixatives Used: • For Pap smears “equal parts” of ether and 95% ethanol or 95% ethanol alone Stains: Papanicolaou/ (H&E) stain/ Romanowsky stain Charecteric feature of cancer cell —> ANAPLASIA
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  IMMUNOHISTOCHEMISTRY - It isan immunological method of identifying the antigenic component in the cell or one of its components by using speci fi c antibodies. - Uses of immunohistochemistry: 1. Categoriztion of undi ff erentiated cancers 2. Determine the origin of poorly di ff erentiated metastatic tumor 3. Select the mode of treatment and to know the prognosis. Immunohistochemical Markers 1. Neuroendocrine tumors show positivity for cytokeratins like carcinomas 2. Neuro fi lament proteins: Marker for tumors of neurons, neuroblastomas and ganglioneuroma. 3. Neuron-speci fi c enolase (NSE) in neuroblastomas. 4. Glial fi brillary acidic protein (GFAP), also intermediate fi lament expressed in glial cell neoplasms. 5. Malignant lymphomas: Generally positive for leukocyte common antigen (LCA, CD45).
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  FLOW CYTOMETRY - Usefulfor Identi fi cation and classi fi cation of tumors of T and B lymphocytes and mononuclear-phagocytic cells. MOLECULAR DIAGNOSIS - Molecular diagnosis can be done by di ff erent techniques like PCR - Diagnosis of cancer - Prognosis of cancer - Detection of minimal residual disease - Detection of hereditary predisposition to cancer - For therapeutic decision: It is useful in target therapy. TUMOUR MARKERS —>