Gene expression profiling spares early breast cancer patients from adjuvant therapy: derived and validated in two population-based cohorts

Table 1 Characteristics of patients operated for breast cancer at the Karolinska Hospital 1994–1996

Patient categories	All patients (n = 524)	No available tissue^a (n = 231)	Excluded for other reasons^b (n = 134)	Included for analysis (n = 159)
Mean age at breast cancer diagnosis (years)	58	57	58	58
Mean tumor size (mm)	20	16	24	22
Proportion of patients with tumor size <21 mm (%)	68	77	57	62
Proportion of patients with positive lymph nodes (%)	26	16	32	38
Proportion deceased (%)	20	12	26	24

^aNo frozen tumors in the tumor bank (n = 231).
^bLiving abroad (n = 7), actively refused participation (n = 6), degraded tumors (n = 42), insufficient amount of RNA (n = 35), not passed the QC for the arrays (n = 12), profiled on the U95 chip (n = 14), neoadjuvant chemotherapy (n = 12), in situ cancer (n = 5) and stage IV at diagnosis (n = 1).

ISSN: 1465-542X