Abstract
BackgroundLobular breast carcinoma usually shows poor responsiveness to chemotherapies and often lacks targeted therapies. Since FGFR1 expression has been shown to play pivotal roles in primary breast cancer tumorigenesis, we sought to analyze the status of FGFR1 gene in a metastatic setting of lobular breast carcinoma, since promising FGFR1 inhibitors has been recently developed.MethodsFifteen tissue metastases from lobular breast carcinomas with matched primary infiltrative lobular breast carcinoma were recruited. Eleven cases showed loco-regional lymph-nodal and four haematogenous metastases.FGFR-1 gene (8p12) amplification was evaluated by chromogenic in situ hybridization (CISH) analysis. Her-2/neu and topoisomerase-IIα gene status was assessed. E-cadherin and Hercept Test were also performed. We distinguished amplification (>6 or cluster of signals) versus gains (3–6 signals) of the locus specific FGFR-1 gene.ResultsThree (20%) primary lobular breast carcinomas showed >6 or cluster of FGFR1 signals (amplification), six cases (40%) had a mean of three (range 3–6) chromogenic signals (gains) whereas in 6 (40%) was not observed any abnormality. Three of 15 metastasis (20%) were amplified, 2/15 (13,4%) did not. The ten remaining cases (66,6%) showed three chromogenic signals.The three cases with FGFR-1 amplification matched with those primary breast carcinomas showing FGFR-1 amplification. The six cases showing FGFR-1 gains in the primary tumour again showed FGFR-1 gains in the metastases. Four cases showed gains of FGFR-1 gene signals in the metastases and not in the primary tumours. Her-2/neu gene amplification was not observed in all cases but one (6%) case. Topoisomerase-IIα was not amplified in all cases.Conclusions1) a subset of metastatic lobular breast carcinoma harbors FGFR-1 gene amplification or gains of chromogenic signals; 2) a minor heterogeneity has been observed after matching primary and metastatic carcinomas; 3) in the era of tailored therapies, patients affected by the lobular subtype of breast carcinoma with FGFR1 amplification could be approached to the new target biological therapy such as emerging FGFR-1 inhibitors.
Highlights
IntroductionThe response to chemotherapy or targeted therapies varies according to histology [1]
In breast carcinoma, the response to chemotherapy or targeted therapies varies according to histology [1]
The data reported show that: 1) FGFR-1 amplification is observed in a subset of lymph-nodal and haematogenous metastases from lobular breast carcinoma; 2) minor heterogeneity is scored in matched primary and metastatic lobular breast carcinomas; 3) in the era of tailored therapies, patients affected by the lobular subtype of breast carcinoma with FGFR-1 amplification may be considered a potential patients’ subset benefiting from FGFR-1 inhibitor
Summary
The response to chemotherapy or targeted therapies varies according to histology [1]. The lobular histotype, the second most common subtype of breast carcinomas (15%), show poor responsiveness to available chemotherapies, rarely implying tailored therapies for patients treatments [2,3]. The Her-2/neu gene is rarely amplified in lobular carcinoma, avoiding trastuzumab therapeutic chances for most the patients, and even worse, the topoisomerase-IIa is constantly not-amplified [2], predicting high chances of chemo-resistance to anthracyclines. In this poor context of medical therapies, new promising predictive biomarkers, giving chances in selecting appropriate patients suitable for receiving new effective regimens, are needed [5,6]. Since FGFR1 expression has been shown to play pivotal roles in primary breast cancer tumorigenesis, we sought to analyze the status of FGFR1 gene in a metastatic setting of lobular breast carcinoma, since promising FGFR1 inhibitors has been recently developed
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