INSR and breast cancer: Table 2 shows the characteristics of BC patients with the division into low and high serum Ir concentration levels according to the median. The analysis with the Chi2 test showed a difference between the groups with high and low Ir expression (division according to the median value, Table 2) only in different age groups of patients (≤60 and >60 years of age). Table 3 shows the associations of Ir serum level with the clinicopathological characteristics in patients with BC.