The study aim is to determine the allele frequencies of 1236 G>A and 3435 G>A in ABCB1 and study their association with the incidence and severity of paclitaxel-induced peripheral neuropathy while adjusting for other baseline covariates in Egyptian patients. Additionally, the study aimed at fitting and validating logistic regression models with the aforementioned SNPs evaluated in additive, dominant, overdominant, and recessive genetic models and performing diagnostics for the best model in terms of internal validity.

Inclusion Criteria:

1. Egyptian females ≥18 years of age.
2. Histologically confirmed Breast Cancer.
3. Receiving conventional neoadjuvant or adjuvant weekly paclitaxel.
4. Eastern Cooperative Oncology Group (ECOG) performance status of 0-2.
5. Adequate organ reserves ((serum creatinine ≤1.5x upper normal limit (UNL), total bilirubin ≤1.5x UNL, absolute neutrophil count ≥1.5 x 10^9/L, platelet count ≥100 x 10^9/L, AST and ALT ≤3.0x UNL, and alkaline phosphatase ≤3.0x UNL).
6. No major neurological disease or symptoms prior to the start of paclitaxel therapy.
7. neither subjective nor objective evidence of metastatic disease.

Exclusion Criteria:

1. Pregnancy.
2. Patients with recurrent or metastatic (local or distant) breast cancer.
3. Neuropathic at the time of recruitment.
4. History of neuropathy prior to recruitment.
5. Previously exposed to taxanes or any other microtubule Inhibitors, or regimens including platinates.
6. Patients currently receiving dose-dense biweekly taxane-containing regimens.

Egyptian women with histologically confirmed Breast Cancer, receiving neoadjuvant and/or adjuvant weekly paclitaxel-containing regimens.