Tumour biomarker expression relative to age and molecular subtypes of invasive breast cancer
Menée sur 162 patientes ayant moins de 40 ans et 100 patientes de plus de 50 ans, toutes atteintes d'un cancer invasif du sein, cette étude met en évidence des différences significatives dans l'expression de divers biomarqueurs en fonction de l'âge des patientes et des sous-types moléculaires de cancer du sein
Background: Quantitative differences in biomarker expression relative to age and molecular subtypes have not been well documented in invasive breast cancer (IBCA).
Methods: Oestrogen receptor (ER), progesterone receptor (PR), HER2, ki67, p53 and DNA ploidy was performed by image analysis in 162 consecutive IBCAs in women (less than or equal to40 years) and compared with women greater than or equal to50 years (100 cases). Molecular subtypes were defined by immunohistochemistry (IHC).
Results: Among young women, tumours were frequently ER negative (P=0.01) with lower ER (P<0.00), PR (P=0.03), higher ki67 index (KI) (P=0.01) and p53 (P=0.00) compared with older women. Triple negative was more frequent among young women with frequent lymph node involvement compared with older women. Luminal B among young vs old women showed lower ER (67% vs 88%), PR (32% vs 52%), higher KI (48% vs 34%) and p53 (19% vs 7%). Linear regression model showed increasing KI (P<0.0001) and p53 (P=0.0003) according to the molecular subtypes. Survival difference among subtypes was demonstrated by multivariate analysis (P=0.0092) after adjusting for age, race, tumour size, grade and stage.
Conclusion: We demonstrated significant differences in biomarker expression relative to age and molecular subtypes. Molecular subtype defined by IHC was an independent prognostic factor.
British Journal of Cancer , résumé, 2011