Table 1

Main patient and tumor characteristics in the two subgroups with and without available tumor samples

No. of patients without available samples N = 347 (%)No. of patients with available formalin- fixed samples N = 430 (%)P
Age (yrs)
 <50187 (54)228 (53)0.89
 ≥50160 (46)202 (47)
Type of surgery
 Conservative125 (36)155 (36)0.94
 Mastectomy222 (64)275 (64)
No. of positive nodes
 1–3194 (56)271 (63)0.07
 ≥4153 (44)159 (37)
ER statusa
 Positive201 (58)275 (64)
 Negative76 (22)99 (23)0.86
 Unknown70 (20)56 (13)
  • a ER, estrogen receptor.