Breast Cancer: An Overview of Introduction, Types, Pathogenesis

Introduction

Table of Contents

Breast cancer is the most common malignancy among women worldwide and a leading cause of cancer-related mortality. It arises from the epithelial cells of the breast, most commonly from the ducts or lobules. Although predominantly affecting women, breast cancer can also occur in men. Early detection and advances in diagnostic and therapeutic strategies have significantly improved survival rates.

Types of Breast Cancer

Breast cancer is classified based on histology, receptor status, and molecular features.

Ductal Carcinoma
- Ductal carcinoma in situ (DCIS) – non-invasive
- Invasive ductal carcinoma (IDC) – the most common type
Lobular Carcinoma
- Lobular carcinoma in situ (LCIS)
- Invasive lobular carcinoma (ILC)
Special Types
- Medullary carcinoma
- Mucinous carcinoma
- Tubular carcinoma
- Inflammatory breast cancer
Molecular Subtypes
- Hormone receptor–positive (ER/PR)
- HER2-positive
- Triple-negative breast cancer (TNBC)

Pathogenesis

Breast cancer develops due to genetic, hormonal, and environmental factors.

Mutations in BRCA1, BRCA2, TP53, and PTEN genes
Prolonged exposure to estrogen
Abnormal cell proliferation and impaired apoptosis
Accumulation of genetic alterations leading to invasion and metastasis
Tumor angiogenesis and immune evasion

Laboratory Diagnosis

Specimens

Breast lump biopsy
Fine-needle aspiration cytology (FNAC)
Core needle biopsy

Diagnostic methods

Histopathological examination – gold standard
Immunohistochemistry (IHC) for ER, PR, HER2
Molecular testing (BRCA mutation analysis)
Tumor markers: CA 15-3, CEA (monitoring)

Treatment

Treatment depends on cancer stage, type, and receptor status.

Surgery: lumpectomy, mastectomy
Chemotherapy
Radiotherapy
Hormonal therapy (tamoxifen, aromatase inhibitors)
Targeted therapy (trastuzumab for HER2-positive tumors)
Immunotherapy (selected cases)

Prevention

Regular breast self-examination
Mammography screening
Genetic counseling for high-risk individuals
Healthy lifestyle: balanced diet, physical activity
Avoidance of alcohol and tobacco
Prophylactic surgery in high-risk cases (BRCA mutation)

Keynotes

The most common cancer in women
Ductal carcinoma is the predominant type
Strong genetic and hormonal influence
Early diagnosis improves prognosis
IHC guides targeted therapy
A multimodal treatment approach is essential.

Breast Cancer: An Overview of Introduction, Types, Pathogenesis,Lab Diagnosis, Treatment, Prevention, and Keynotes