Pathology 6

• Lai Shau Kong, MD, DrPATH, is a Pathologist (Anatomical) in the Department of Pathology, UPM.
• Clinical aspects of neoplasia include effects of tumour on the host, cancer grading and cancer staging, and laboratory diagnosis of tumour.
• Local effects of tumour can be secondary to local growth, invasion, or metastasis, and the location of a tumour is a critical determinant of clinical effects.
• Serum Tumour Markers are biochemical assays that detect tumour-associated proteins, hormones, oncofetal antigens, lineage-specific proteins, mucin, and are mostly used for monitoring response to cancer therapy.
• DNA Tumour Markers can detect multiple driver mutations in a single specimen simultaneously, such as TP53, APC, RAS mutants in stool and serum.
• The evolution of cancer treatment has included diagnosis, treatment, and epilogue.
• Pancreatic cancer can be detected using DNA Tumour Markers that identify TP53 and RAS mutants in stool and serum.
• The level of PSA in the blood can be used to monitor the response to cancer therapy, normalizing after complete surgical removal and resurging during tumour recurrence.
• Such markers may not exist as cancer has multiple genetic and epigenetic events rather than singular events.
• Colon cancer can be detected using DNA Tumour Markers that identify TP53 and RAS mutants in stool and serum.
• DNA Tumour Markers are identified in urine, blood, or stool and are used to identify specific driver mutations, but they lack the specificity to allow screening of populations.
• Lung cancer can be detected using DNA Tumour Markers that identify TP53, RAS mutants in sputum and serum.
• PSA (Prostate-Specific Antigen) is a Serum Tumour Marker used in the diagnosis of prostate cancer.
• Serum Tumour Markers mostly lack the sensitivity and specificity necessary for cancer screening.
• Cancer cachexia is a hypercatabolic state, loss of muscle mass, and loss of fat, and cannot be explained by diminished food intake.
• Cancer cachexia is responsible for about 30% of cancer deaths and its symptoms include extreme weight loss, fatigue, muscle atrophy, anaemia, anorexia, and oedema.
• Cancer cachexia generally results in the atrophy of the diaphragm and other respiratory muscles.
• Pathophysiology of cancer cachexia involves inflammatory mediators (TNF, IL-1, and IL-6), cytokines, lipid mobilizing factor, and hormonal effects.
• Endocrine tumour can cause hormonal effects and benign tumour are more common than malignant tumours.
• Insulinoma is a benign pancreatic islets beta-cell tumour that may produce insulin to cause fatal hypoglycaemia, even if it is less than 1 cm in diameter.
• Non-endocrine tumour can elaborate hormones or hormone-like products and paraneoplastic syndromes are signs and symptoms that cannot be explained by local effect or indigenous tissue hormonal effects.
• Malignant cells are difficult to identify as being of squamous origin and require ancillary tests such as immunohistochemical (IHC) staining.
• Molecular techniques include karyotyping, FISH (fluorescence in situ hybridization), PCR (polymerase chain reaction), DNA sequencing, and DNA microarrays.
• Cytology principles involve judgment based on the features of individual cells (or cell groups) and permits differentiation among normal, dysplastic, and malignant cells.
• Adjunct (Ancillary) Diagnostic Techniques are used for accurate identification as treatment and prognosis are different, categorization of undifferentiated malignant tumours, and determining the origin of metastatic tumours.
• Flow cytometry is a rapid, multiplex, quantitative technique to identify cellular characteristics and antigens expressed in viable, “liquid tumours” or blood-forming tissues using antibodies.
• Paraneoplastic endocrinopathies are non-endocrine cancers with ectopic hormone production and secretion, such as Cushing syndrome and paraneoplastic hypercalcemia.
• Molecular techniques such as cytogenetics, FISH, PCR can detect translocations.
• Fine-Needle Aspiration Cytology (FNAC) involves aspirating cells and fluid with a small-bore needle, followed by cytologic examination of the stained smear.
• Immunohistochemistry for tissue-specific or organ-specific antigens can determine the origin of metastatic tumours.
• PCR can detect translocations.
• The 50-year-old male with a lung mass had a 11;22(q24;q12) translocation, which is characteristic of Ewing sarcoma.
• Immunohistochemistry uses antibodies to identify target antigens (protein) expression in tissue.
• Exfoliative and Effusion Cytology involves screening for carcinoma and its precursor lesions, and any suspected malignancy in which tumour cells are shed into fluids or are easily accessible.
• Immunohistochemistry for tissue type-specific proteins can determine the origin of metastatic tumours.
• Paraneoplastic neuromyopathic syndromes are cancer-induced immunologic attacks on nerves.
• TNM staging scheme and criteria for solid cancers are: T for primary tumour, N for regional lymph nodes, and M for metastasis.
• Grade of cancer is determined by the differentiation of tumour cells and may include mitotic count or architectural features.
• Staging of solid cancers is based on the size of primary lesion, spread to regional lymph nodes, and presence of blood-borne metastases.
• Nerve and muscle syndromes are conditions that affect the nerves and muscles.