IBYME   02675
INSTITUTO DE BIOLOGIA Y MEDICINA EXPERIMENTAL
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
INVASIVE MICROPAPILLARY CARCINOMA OF THE BREAST OVEREXPRESSES MUC4 AND IS ASSOCIATED WITH POOR RESPONSE TO TRASTUZUMAB IN HER2-POSITIVE BREAST CANCER
Autor/es:
DE MARTINO MARA; CORDO RUSSO ROSALÍA INÉS; FIGURELLI SILVINA; ARES SANDRA; SCHILLACI ROXANA; INURRIGARRO GLORIA; RIVAS MARTÍN ALFREDO; FERNÁNDEZ ELMER ANDRÉS; GIL DEZA ERNESTO; ELIZALDE PATRICIA; MERCOGLIANO MARÍA FLORENCIA; VENTURUTTI LEANDRO; PROIETTI CECILIA JAZMÍN; BARCHUK SABRINA ; GERCOVICH FELIPE
Reunión:
Congreso; Reunión Conjunta de Sociedades de Biociencias- LXII Reunión Anual de la Sociedad Argentina de Investigación Clínica (SAIC); 2017
Resumen:
Invasive micropapillary carcinoma of the breast (IMPC)is a low-frequent tumor variant (~6% of all breast cancers) characterized by aninside-out formation of tumor clusters surrounded by stroma with apseudopapillary arrangement and it has a poor clinical outcome that does not correlate with the number of micropapillaryfeatures. Pathologists underreport IMPC because it is difficult to identify andthere are no biomarkers available. HER2-positive breast cancers (HER2+ BC) have an aggressive behavior.This subtype is treated with trastuzumab (TZ) but 40-60% of the patientsdo not respond to therapy due to resistance. We recently demonstrated that TNFα-induced mucin 4 (MUC4, membrane glycoprotein thatpromotes metastasis dissemination) expression in HER2+ BC is a biomarker ofpoor prognosis to adjuvant TZ.Here we studied the clinical significance of IMPC andMUC4 expression in HER2+ BC patients.We retrospectively studied 86 HER2+ BCpatients treated with TZ in the adjuvant setting. We explored the associationbetween IMPC and clinicopathological parameters at diagnosis and its prognostic value.IMPC, either as a pure entity or associated withinvasive ductal carcinoma (IDC), was present in 18.6% of HER2+ cases. It waspositively correlated with estrogen receptor expression and tumor size, butinversely correlated with patient's age. Disease-free survival wassignificantly lower in patients with IMPC (hazard ratio= 2.6; 95%, confidenceinterval 1.1-6.1, P = 0.0340). MUC4 was strongly expressed in all IMPC casestested. IMPC appeared as the histological breast cancer subtype with thehighest MUC4 expression with respect to IDC, lobular and mucinous carcinoma(P<0.05).These results show that IMPC presence in HER2+ BCshould be carefully examined and we therefore propose MUC4 expression as a usefulbiomarker to determine its presence. Patients with MUC4+ tumors with IMPC should be more frequently monitored and receive moreaggressive therapies.