**5.2 Stage 1**

Invasive breast cancer is described as this stage, and microscopic invasion is conceivable. It is divided into two stages: 1A and 1B. Te category 1A refers to a tumour that is up to 2 cm in diameter and does not include any lymph nodes, while stage 1B refers to a tiny collection of cancer cells bigger than 0.2 mm discovered in a lymph node [17].

*The Future Perspectives of Drug Repurposing and Treatment for the Drug Resistant Breast… DOI: http://dx.doi.org/10.5772/intechopen.100143*
