Page 163 - Concise Pathology for Exam Preparation ( PDFDrive )

148 SECTION I General Pathology

microfilaments and microtubules, intermediate filaments do not participate in cell motility.
In higher vertebrates, the subunits composing intermediate filaments constitute a superfam-
ily of highly a-helical proteins that is divided into subtypes on the basis of similarities in
sequence (Table 6.10).

TABLE 6.10. ‘Intermediate filaments’ and their significance in the
tumour diagnosis

Keratins Carcinomas, mesotheliomas and germ-cell tumours
Vimentin Sarcomas, melanomas and lymphomas (mesenchymal
tumours)
Desmin Myogenic tumours
Neurofilaments Neural tumours
Glial fibrillary acidic proteins Glial tumours

6. Electron microscopy (EM): EM is used for confirming or substantiating tumour
diagnosis based on:
(a) Presence and type of cell junctions
(b) Presence of microvilli
(c) Shape of nucleus, features of nuclear membrane and nucleoli
(d) Cytoplasmic organelles
(e) Presence of dense bodies in the cytoplasm
7. Tumour markers: These are substances found in blood, urine, body fluids or tissue,
the levels of which might be elevated in association with a cancer. Tumour markers may
be used to help diagnose cancer, predict a patient’s response to cancer therapy, check a
patient’s response to treatment or determine cancer recurrence. More than 20 tumour
markers are currently in use (Table 6.11).

TABLE 6.11. Role of tumour markers in neoplasia

Tumour marker Associated neoplasm
AFP (a-fetoprotein) Hepatocellular carcinoma, nonseminomatous-germ-cell
tumours
PSA (prostate-specific antigen) Prostatic carcinoma
HCG (human chorionic gonadotropin) Trophoblastic tumours
Calcitonin Medullary carcinoma of thyroid
Vanillylmandelic acid (VMA) Pheochromocytoma
CA-125 Carcinoma of ovary
CEA (carcinoembryonic antigen) Cancer of bowel, pancreas and breast
CA-15.3 Carcinoma of breast

Modern Aids in the Tumour Diagnosis

1. Flow cytometry: Recognition and quantification of several parameters simultaneously
by making single-cell suspensions of cells, which are made to pass through a chamber
in a single file. Fluids, blood and bone marrow can be processed directly; whereas,
homogenization is necessary for solid tissue. Each cell is struck by a focused laser
beam, and the properties of scattered and fluorescent light is measured to characterize
the cell.

DNA content (aneuploidy is associated
Material is analyzed for with poor prognosis)
Identification of cell surface antigens

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