Methods of assigning treatment to breast cancer patients

A method of assigning a treatment to a breast cancer patient, wherein said breast cancer patient is a human breast cancer patient, comprising:

• (a) determining the lymph node status for said breast cancer patient;
• (b) determining the nucleic acid levels of expression of at least five genes listed in Table 5 in a clinically relevant cell sample from said breast cancer patient, thereby generating a first expression profile comprising the nucleic acid levels of expression of said at least five genes in said cell sample;
• (c) classifying said breast cancer patient as having a prognosis selected from the group consisting of a first prognosis, a second prognosis, and a third prognosis by a method comprising
• (c1) determining the similarity between said first expression profile and a first good prognosis expression profile comprising the nucleic acid levels of expression of said at least five genes to obtain a patient similarity value, wherein said nucleic acid levels of expression in said good prognosis expression profile represent the nucleic acid levels of expression of said genes in breast cancer patients having no distant metastases within five years of initial diagnosis;
• and
• (c2) classifying said breast cancer patient as having said first prognosis if said patient similarity value exceeds a second similarity threshold value, said second prognosis if said patient similarity value exceeds a first similarity threshold value but does not exceed said second similarity threshold value, and said third prognosis if said patient similarity value does not exceed said first similarity threshold value, wherein said second similarity threshold value indicates greater similarity to said first good prognosis expression profile than does said first similarity threshold value;
• and
• (d) assigning said breast cancer patient a treatment without adjuvant chemotherapy if the breast cancer patient is lymph node negative and is classified as having said first prognosis or said second prognosis, or assigning said breast cancer patient a treatment with adjuvant chemotherapy if said breast cancer patient (d1) is lymph node positive and is classified as having said first prognosis, said second prognosis, or said third prognosis, or (d2) is lymph node negative and is classified as having said third prognosis.