Table 1.

Tumor characteristics for different breast cancer subtypes among 804 women with invasive breast cancer participating in the Polish Breast Cancer Study

CharacteristicsLuminal ALuminal BHER2-expressingBasal-likeUnclassifiedP*
No. (% of total)552 (69)48 (6)61 (8)95 (12)48 (6)
Histology, no. (%)
    Ductal308 (56)36 (75)54 (89)63 (80)36 (57)
    Lobular128 (23)5 (10)3 (5)8 (10)10 (16)<0.0001
    Mixed and other66 (21)7 (14)4 (7)8 (10)17 (27)Not determined
Tumor grade, no. (%)
    Well differentiated149 (27)1 (2)0 (0)2 (2)7 (15)
    Moderately differentiated345 (62)30 (63)22 (36)25 (26)26 (54)
    Poorly differentiated58 (11)17 (35)39 (64)68 (72)15 (31)<0.0001
Tumor size (cm), no. (%)
    ≤2332 (60)16 (33)19 (32)36 (38)14 (29)
    >2218 (40)32 (67)41 (68)59 (62)34 (71)<0.0001
Axillary node metastasis, no. (%)
    Negative330 (61)24 (52)26 (43)54 (57)26 (54)
    Positive210 (39)22 (48)35 (57)40 (43)22 (46)0.06
  • NOTE: Tumor subtypes were defined as luminal A (ER+ and/or PR+, HER2−), luminal B (ER+ and/or PR+, HER2+), HER2 (HER2+, ER−, PR−), basal-like (ER−, PR−, HER2−, CK5+, and/or HER1+), and unclassified or normal-like (negative for all five markers; ref. 4).

  • * P values were obtained by comparing the five tumor subtypes using χ2 test for differences in frequencies.

  • Well and moderately differentiated tumors were combined into one category for P value calculation.