Breast Carcinomas: General Hypotheses, Risk Factors, and Biological Behaviour - A Comprehensive Review

Breast carcinomas represent a heterogeneous group of malignant neoplasms that constitute the most frequently diagnosed cancer amongst women worldwide, with an estimated 2.3 million new cases annually according to recent global cancer statistics. This comprehensive review examines the current understanding of breast carcinoma pathogenesis, encompassing the multifaceted hypotheses underlying tumour development, the complex array of risk factors contributing to disease susceptibility, and the diverse biological behaviours exhibited by different molecular subtypes. The pathogenesis of breast carcinomas involves a multistep process characterised by the accumulation of genetic alterations and environmental influences, progressing from normal epithelial cells through hyperplasia, premalignant changes, and in situ carcinoma to invasive disease. Risk factors are categorised into non-modifiable elements including female sex, advancing age, genetic mutations, and family history, alongside modifiable factors such as hormonal replacement therapy, lifestyle choices, and environmental exposures. The biological behaviour of breast carcinomas varies significantly across molecular subtypes, with luminal A tumours demonstrating indolent growth patterns and favourable prognosis, whilst triple-negative breast cancers exhibit aggressive characteristics with propensity for early metastasis and treatment resistance. Contemporary molecular classification systems, incorporating immunohistochemical assessment of oestrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 expression, have revolutionised therapeutic approaches and prognostic stratification. Understanding the intricate relationships between genetic predisposition, environmental influences, and tumour biology remains paramount for advancing personalised treatment strategies and improving patient outcomes. This review synthesises current evidence regarding breast carcinoma aetiology, risk stratification, and biological characteristics, providing a foundation for future research directions and clinical applications in breast cancer management.