Table 1

CK18a expression of primary breast tumors in relation to histopathological factors

Characteristics of primary carcinomasbCK 18 expressionP
Normal expression (n = 1087)Partial and complete loss of CK18 expression (n = 371)
Histological type
 Ductal carcinoma (n = 1042)777 (74.6%)265 (25.4%)0.002
 Lobular carcinoma (n = 188)156 (83%)32 (17.0%)
 Other (n = 228)c154 (67.5%)74 (32.5%)
Tumor size
 pT1 (n = 497)394 (79.3%)103 (20.7%)0.008
 pT2 (n = 676)483 (71.4%)193 (28.6%)
 pT3 (n = 94)64 (68.1)30 (31.9%)
 pT4 (n = 185)142 (76.8%)43 (23.2%)
Grading
 G1 (n = 330)284 (86.1%)46 (13.9%)0.0001
 G2 (n = 566)452 (79.9%)114 (20.1%)
 G3 (n = 474)286 (60.3%)188 (39.7%)
Lymph node status
 pN0 (n = 585)429 (73.3%)156 (26.7%)0.640
 pN1/2 (n = 620)462 (74.5%)158 (25.5%)
Mitotic indexd
 1 (n = 693)580 (83.7%)113 (16.3%)0.0001
 2 (n = 256)192 (75%)64 (25%)
 3 (n = 417)248 (59.5%)169 (40.5%)
Age
 ≤ 50 (n = 250)185 (74%)65 (26%)0.855
 > 50 (n = 937)688 (73.4%)249 (26.6%)
  • a CK, cytokeratin.

  • b Data from tumor size, lymph node status, grading, and age were not available in 6, 253, 88, and 271 cases, respectively.

  • c This group can be subdivided into medullary carcinoma (n = 50), mucinous carcinoma (n = 46), cribriform carcinoma (n = 37), tubular carcinoma (n = 34), papillary carcinoma (n = 18), apocrine carcinoma (n = 11), clear cell carcinoma (n = 9), atypic medullary carcinoma (n = 6), metaplastic carcinoma (n = 4), neuroendocrine carcinoma (n = 2), and adenoid cystic carcinoma (n = 1). Ten breast carcinoma samples were not histologically specified.

  • d M1 = <10 mitoses per high power field (HPF), M2 = 10–20 mitoses per HPF, and M3 ≧ 20 mitoses per HPF.