Different distribution of breast cancer subtypes in breast ductal carcinoma in situ (DCIS), DCIS with microinvasion, and DCIS with invasion component.
BACKGROUND
Breast ductal carcinoma in situ with microinvasion (DCIS-Mi) is considered to be the interim stage in the progression from DCIS to invasive breast cancer (IDC). Cases that exceed DCIS-Mi but still do not fulfill the diagnostic criteria of IDC often are observed. We define those cases as DCIS with invasion component (DCIS-I), and attempt to study the differences of clinicopathological features and immunohistochemical-based subtypes among DCIS, DCIS-Mi, and DCIS-I.


METHODS
In this retrospective study, 550 consecutive DCIS patients were recruited, 271 (49.3%) cases were diagnosed as pure-DCIS, 67 as DCIS-Mi, and 212 as DCIS-I. They were categorized into four groups: luminal-A (ER+ and/or PR+, HER2-), luminal-B (ER+ and/or PR+, HER2+), ERBB2+ (ER-, PR-, HER2+), and basal-like (ER-, PR-, HER2-).


RESULTS
DCIS-Mi and DCIS-I patients tended to have larger tumors with highly graded nuclear (P = 0.011 for size; P < 0.0001 for nuclear grade). The proportion of luminal-like tumors decreased, whereas ERBB2+ and basal-like tumors increased in DCIS-I/DCIS-Mi compared with pure-DCIS (P = 0.039). Although the HER2-positive tumors displayed a stable proportion among DCIS subgroups, the essences of them were varying. In pure-DCIS, luminal-B was the major subtype of HER2-positive tumors (luminal-B vs. ERBB2+, 19% vs. 14.6%), whereas in DCIS-I, the proportion of luminal-B decreased vastly (luminal-B vs. ERBB2+, 12.8% vs. 23.5%). DCIS-I had a worse relapse-free survival outcome compared with pure-DCIS.


CONCLUSIONS
Different distribution of subtypes and distinctive characteristics among DCIS, DCIS-Mi, and DCIS-I indicate that they are distinct entities. Further studies with larger sample size are needed to replicate our observations.
Department of Breast Surgery, Fudan University, Shanghai, People's Republic of China.
Ke-Da
KD
Yu
La-Mu
LM
Wu
Guang-Yu
GY
Liu
Jiong
J
Wu
Gen-Hong
GH
Di
Zhen-Zhou
ZZ
Shen
Zhi-Ming
ZM
Shao
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000378:metabolism / Q000401:mortality / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism / Q000401:mortality / Q000473:pathology*; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000378:metabolism / Q000401:mortality / Q000473:pathology*; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012189:Retrospective Studies; D015996:Survival Rate
D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone