Beyond MEN1, when to think about MEN4? Retrospective study on 5600 patients in the French population & literature review

CONTEXT

Germline CDKN1B variants predispose patients to multiple endocrine neoplasia type 4 (MEN4), a rare MEN1-like syndrome, with <100 reported cases since its discovery in 2006. Although CDKN1B mutations are frequently suggested to explain cases of genetically-negative MEN1, the prevalence and phenotype of MEN4 patients is poorly known, and genetic counseling is unclear.

OBJECTIVE

To evaluate the prevalence of MEN4 in MEN1-suspected patients and characterize the phenotype of MEN4 patients.

DESIGN

Retrospective observational nationwide study. Narrative review of literature and variant class reassessment.

PATIENTS

We included all adult patients with class 3/4/5 CDKN1B variants identified by the laboratories from the French TENGEN network between 2015 and 2022 through germline genetic testing for MEN1 suspicion. After class reassessment, we compared the phenotype of symptomatic patients with class 4/5 CDKN1B variants, i.e. with genetically-confirmed MEN4 diagnosis, in our series and in literature with 66 matched MEN1 patients from the UMD-MEN1 database.

RESULTS

From 5600 MEN1-suspected patients analyzed, four patients with class 4/5 CDKN1B variant were found (0.07%). They presented with multiple duodenal NET, PHPT and adrenal nodule, isolated PHPT, PHPT and pNET. We listed 29 patients with CDKN1B class 4/5 variants from literature. Compared to matched MEN1 patients, MEN4 patients presented lower NET incidence and older age at PHPT diagnosis.

CONCLUSION

The prevalence of MEN4 is low. PHPT and PA represent the main associated lesions, NETs are rare. Our results suggest a milder and later phenotype than in MEN1. Our observations will help to improve genetic counseling and management of MEN4 families.

PERCEPTION Trial protocol: Comparison of predictive and prognostic capacities of neutrophil, lymphocyte, and platelet counts and tumor-infiltrating lymphocytes in triple negative breast cancer

BACKGROUND

Triple negative breast cancer affects 10% to 20% of all women diagnosed with breast cancer. Due to its characteristics, treatment strategies are limited and metastatic recurrences are common in the first 5 years after treatment. However, not all patients affected by this disease develop metastases. Tumor-infiltrating lymphocytes have shown to be reliable predictive biomarkers of treatment response and metastatic recurrences. However, we need to develop simpler and faster ways to predict response to cytotoxic treatment and the possibility of eventual cancer relapse by identifying new biomarkers. Recently, new studies are emerging, suggesting a predictive role of circulating blood cells in different types of cancer. In this study, we will assess the correlation between tumor-infiltrating lymphocytes and different elements of the blood count in patients diagnosed with triple negative breast cancer.

METHODS

The main objective of this study is to evaluate the correlation between the peripheral neutrophil-to-lymphocyte ratio and the amount of tumor-infiltrating lymphocytes, assessed in triple negative breast cancer patients at diagnosis. Secondary objectives include evaluation of the correlation between tumor-infiltrating lymphocytes at diagnosis and the baseline absolute neutrophil, lymphocyte, and platelet counts, as well as the platelet-to-lymphocyte ratio. The triple negative breast cancer patients will be enrolled in the PERCEPTION trial during the first year after the treatment completion. Two supplementary blood tests, at 12 months after the end of treatment and at the time of the first metastatic recurrence, will be performed.

DISCUSSION

The discovery of new prognostic and predictive biomarkers is crucial for triple negative breast cancer. We set up the PERCEPTION clinical trial in order to evaluate certain blood counts as early biomarkers and to assess their correlation with tumor-infiltrating lymphocytes. Demonstration of comparative predictive and/or prognostic capacities of peripheral blood counts and tumor-infiltrating lymphocytes would allow introduction of the former as simple and cheap biomarkers in triple negative breast cancer patient management.

TRIAL REGISTRATION

The PERCEPTION study has been registered in the French National Agency of Medical Security registry on the 2nd of July 2019 under the number 2019-A01861-56 and in the ClinicalTrials.org registry under the number NCT04068623.

XENOBREAST Trial: A prospective study of xenografts establishment from surgical specimens of patients with triple negative or luminal b breast cancer

Introduction: Patient-derived xenografts (PDX) can be used to explore tumour pathophysiology and could be useful to better understand therapeutic response in breast cancer. PDX from mammary tumours are usually made from metastatic tumours. Thus, PDX from primary mammary tumours or after neoadjuvant treatment are still rare. This study aims to assess the feasibility to establish xenografts from tumour samples of patients with triple negative or luminal B breast cancer in neoadjuvant, adjuvant or metastatic setting.

Methods: XENOBREAST is a single-centre and prospective study. This feasibility pilot trial aims to produce xenografts from tumour samples of patients with triple negative or luminal B breast cancer. Patient enrolment is expected to take 3 years: 85 patients will be enrolled and followed for 28 months. Additional blood samples will be taken as part of the study. Surgical specimens from post-NAC surgery, primary surgery or surgical excision of the metastases will be collected to establish PDX. Histomolecular characteristics of the established PDX will be investigated and compared with the initial histomolecular profile of the collected tumours to ensure that they are well-established.

Ethics and dissemination: XENOBREAST belongs to category 2 interventional research on the human person. This study has been approved by the Sud Méditerranée IV – Montpellier ethics committee. It is conducted notably in accordance with the Declaration of Helsinki and General Data Protection Regulation (GDPR). Study data and findings will be published in peer-reviewed medical journals. We also plan to present the study and all data at national congresses and conferences.

Registration: ClinicalTrials.gov ID NCT04133077; registered on October 21, 2019.