Inclusion Criteria:

- Patients who have given their written informed consent to participate in the study.

- Women over 18 years.

- Breast cancer locally recurrent or metastatic at first relapse or after
successive progressions.

- Patient has to have available a sample of the primary tumor in paraffin.

- Patients who are planning for the next 6 weeks, the biopsy (fine needle
aspiration / drainage of fluid cavities, open biopsy, core biopsy) of locally
recurrent or metastatic lesion [local relapse in the chest wall, nodal ,
cutaneous or subcutaneous metastases, peripheral lymph nodes and other soft
tissues accessible, bone metastases, visceral metastases (lung, liver, brain,
etc..) or pleural effusion / ascites / pericardial / cerebrospinal] according to
clinical practice center.

Exclusion Criteria:

- Patients with cognitive impairment that might impede a proper understanding of the
written informed consent, according to medical criteria.

- ipsilateral breast local relapses or contralateral breast away.

- Patients diagnosed with a second neoplasm, with the exception of cervical carcinoma
in situ and non-melanoma skin carcinoma treated properly.