This study aims to investigate the correlation between paclitaxel-induced neuropathy and the measurement values of serum IL-20 levels at baseline and during chemotherapy in patients who will receive neoadjuvant or adjuvant paclitaxel chemotherapy with the diagnosis of early-stage or locally advanced breast cancer

• Patients with the diagnosis of breast cancer who will be started on adjuvant or neoadjuvant paclitaxel chemotherapy will be included in the study.
• Patients who will receive standard breast cancer treatment (4 cycles of cyclophosphamide 600mg/m2 every 21 days + epirubicin 90mg/m2 followed by weekly paclitaxel 80 mg/m2 x 12 sessions) will be included in the study.
• Age, gender, additional disease, diagnosis dates, previous diseases and breast cancer subtypes of the patients who signed the informed consent form will be obtained from the electronic information system or by asking face-to-face.
• Serum IL-20 level will be studied from blood tests taken for routine chemotherapy. no extra blood sample will be taken for the study
• Neuropathy assessment will be evaluated with Organisation for Research and Treatment of Cancer (EORTC) chemotherapy-induced peripheral neuropathy (QLQ-CIPN20) Questionnaire, the sensitivity, and specificity of which have previously been demonstrated for chemotherapy-induced neuropathy. The Turkish validation questionnaire of the study, which was made before, will be conducted by the physician in charge before the paclitaxel chemotherapy and at the 1st and 12th weeks after the treatment, by asking the patient face to face.
• patients with diabetes mellitus and patients who had a history of peripheral neuropathy will be excluded from the study.

Inclusion Criteria:

• patients receiving paclitaxel chemotherapy for local advanced or early-stage breast cancer
• >18 years

Exclusion Criteria:

• advanced stage breast cancer
• having before peripheral neuropathy
• patients with diabetes mellitus
• < 18 years

only the female gender will be enrolled

Patients receiving standard breast cancer treatment containing taxane