Biology, prognosis and response to therapy of breast carcinomas according to HER2 score.
BACKGROUND
The standardization of the HER2 score and recent changes in therapeutic modalities points to the need for a reevaluation of the role of HER2 in recently diagnosed breast carcinoma.


METHODS
A multicenter, retrospective study of 1794 primary breast carcinomas diagnosed in Italy in 2000/2001 and scored in HER2 four categories according to immunohistochemistry was conducted.


RESULTS
Ductal histotype, vascular invasion, grade, MIB1 positivity, estrogen and progesterone receptor expression differed significantly in HER2 3+ tumors compared with the other categories. HER2 2+ tumors almost showed values intermediate between those of the negative and the 3+ subgroups. The characteristics of HER2 1+ tumors were found to be in between those of HER2 0 and 2+ tumors. With a median follow-up of 54 months, HER2 3+ status was associated with higher relapse rates in node-positive and node-negative subgroups, while HER2 2+ only in node positive. Analysis of relapses according to type of therapy provided evidence of responsiveness of HER2-positive tumors to chemotherapy, especially taxanes.


CONCLUSIONS
The present prognostic significance of HER2 is correlated to receptor expression level and points to the need to consider HER2 2+ and HER2 3+ tumors as distinct diseases with different outcomes and specific features.
Department of Experimental Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. sylvie.menard@istitutotumori.mi.it
S
S
Ménard
A
A
Balsari
E
E
Tagliabue
T
T
Camerini
P
P
Casalini
R
R
Bufalino
F
F
Castiglioni
M L
ML
Carcangiu
A
A
Gloghini
S
S
Scalone
P
P
Querzoli
M
M
Lunardi
A
A
Molino
M
M
Mandarà
M
M
Mottolese
F
F
Marandino
M
M
Venturini
C
C
Bighin
G
G
Cancello
E
E
Montagna
F
F
Perrone
A
A
De Matteis
A
A
Sapino
M
M
Donadio
N
N
Battelli
A
A
Santinelli
L
L
Pavesi
A
A
Lanza
F A
FA
Zito
A
A
Labriola
R A
RA
Aiello
M
M
Caruso
F
F
Zanconati
G
G
Mustacchi
M
M
Barbareschi
M
M
Frisinghelli
R
R
Russo
G
G
Carrillo
D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000201:enzymology* / Q000473:pathology / Q000628:therapy*; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008408:Mastectomy; D008875:Middle Aged; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis*; D012189:Retrospective Studies
D018931:Antineoplastic Agents, Hormonal; D018719:Erb-b2 Receptor Tyrosine Kinases