This is a prospective examination of tumor material of breast cancer patients randomized into the FinHer-trial (= (= Comparison of vinorelbine and docetaxel and trastuzumab as adjuvant treatments of breast cancer patients wirh a high risk of cancer recurrence).

The formalin-fixed, paraffin-embedded tissue samples will be analysed for Estrogen receptor 1 (ESR1), progesterone receptor (PgR), Human epidermal growth factor receptor 2 (HER2) and Antigen Ki-67 (Ki-67) with the molecular in vitro diagnostic kit MammaTyper™.

According to the new subtyping the 5 year Distant disease free survival (DDFS) and Overall survival (OS) will be re-evaluated.

Despite the fact that reliable measures for the markers ESR1, PgR, HER2, Ki-67 are necessary with the currently used methods up to 20% of determinations are inaccurate and especially Ki67- measures are not very reproducible. Therefore new evaluation systems or new methods are necessary to improve diagnostic.

At least 4 subtypes can be distinguished to date depending on the expression of ESR, PgR, Her2 and Ki-67:

• Luminal A-type
• Luminal B-type
• Her2-type
• Triple-negative-type

MammaTyper™ uses a new approach. Instead of detection of the marker proteins, the messenger ribonucleic adic (mRNA) of marker proteins is quantitated. This prospectively planned diagnostic study will investigate the potential of subgrouping of patients at baseline according to results of MammaTyper™ methodology for predicting survival.

Patients will be subgrouped according to the new marker determination and the DDFS and OS will be evaluated and compared to the DDFS and OS of subgrouping with former marker determination.

Inclusion Criteria:

• Invasive breast cancer verified in a histological biopsy
• Age 65 or younger
• Estrogen receptor (ER), PgR and HER2 expression have been determined
• No distant metastases present (M0)
• The patient provides a written informed consent for study participation
• The estimated risk of breast cancer recurrence is high (25% or higher within the first 5 years from the date of the diagnosis, over >35% within the first 10 years from the diagnosis)

Exclusion Criteria:

• Patients with breast cancer with "a special histological type" (mucinous, papillary, medullary, or tubular type of breast cancer) when no metastases are present in the ipsilateral axillary lymph nodes
• The WHO performance status is moderate/poor, Z >1
• The peripheral blood leukocyte count is less than 3.0 x 109/L, the blood granulocyte count is less than 1.5 x 109/L, or the blood thrombocyte count is less than 120 x 109/L
• Any physical or mental disorder that is considered to prohibit administration of chemotherapy
• Cardiac failure; severe cardiac arrythmia requiring regular medication

Clinical data and breast tumour tissue samples were collected within the FinHer trial (identifier ISRCTN76560285).