Laboratory Diagnosis of Cancer

Methods and Techniques for Diagnosing Cancer

Introduction

Welcome to Pathology Made Simple tutorial on the laboratory diagnosis of cancer
In this presentation, we will discuss various methods utilized to diagnose cancer and their utilities in cancer management
Physicians thoroughly examine patients for vague symptoms and clues for cancer diagnosis
Routine blood investigations can reveal anemia or polycythemia, which may be secondary to underlying malignancy

Cytopathological examination involves studying cells for cancer diagnosis
Cells for diagnosis can be obtained through exfoliative cytology or interventional cytology
Exfoliative cytology involves spontaneously shed cells from organ linings, such as Pap smears for cervix lesions
Interventional cytology involves obtaining cells through active intervention, e.g., fine needle aspiraion cytology

Histopathological examination involves diagnosing cancer based on microscopic features of the neoplasm
Tissues for examination can be obtained through needle biopsy, endoscopic biopsy, incision biopsy, or excision biopsy
Needle biopsy involves taking a small chunk of tissue through a core needle
Endoscopic biopsy is performed during gastrointestinal endoscopy procedures
Incision biopsy involves taking a part of the lesion along with normal tissue
Excision biopsy involves removing the entire tumor along with surrounding tissue

Immunohistochemistry is a special investigation used to detect specific proteins in tissue sections
Antibodies are used to recognize and bind to the target proteins
Markers are used to visualize the antigen-antibody complex
Immunohistochemistry helps in determining the nature of the tumor, extent of tumor involvement, and categorizing undifferentiated cancer

Flow cytometry is a technique used to analyze cell properties as they pass through a fluid stream
Light scattering is used to obtain information about the cells
Flow cytometry helps in identification and characterization of specific types of cancers

Molecular techniques involve studying the genetic makeup of cancer cells
Polymerase Chain Reaction (PCR) is used to detect and amplify specific DNA sequences
Fluorescence in situ hybridization (FISH) is used to detect genetic changes and chromosomal abnormalities
Gene sequencing is used to identify mutations and other genetic changes
Next Generation Sequencing (NGS) is an advanced method for reading DNA in a short amount of time

Imaging techniques like X-rays, ultrasound, computed tomography (CT) scan, magnetic resonance imaging (MRI), and positron emission tomography (PET) are used in cancer diagnosis
Each technique uses different technologies to produce detailed images of the body
Imaging techniques can be used alone or in combination for diagnosing cancers

Liquid biopsy is a technique that uses blood to detect the genetic makeup of cancers
Circulating tumor DNA (ctDNA) test detects DNA shed by cancer cells in the blood
Liquid biopsy provides real-time information about the presence of cancer and can be used to monitor response and detect minimal residual disease

Tumor markers are products of tumors that can be detected in cells, blood, or body fluids
Tumor markers can be used to monitor the progression of the disease and evaluate the effectiveness of cancer treatment
Examples of tumor markers include prostate-specific antigen (PSA), cancer antigen 125 (CA125), and alpha-fetoprotein (AFP)

In conclusion, the laboratory diagnosis of cancer involves multiple methods and techniques
Each method has its own advantages and utilities in cancer diagnosis and management
A combination of physical examination, laboratory investigations, imaging, and molecular techniques provides a comprehensive approach to cancer diagnosis
It is important to integrate these diagnostic methods for accurate and conclusive cancer diagnosis