The laboratory at the Eugène Marquis Centre carries out general and specialist biochemistry testing, haematology testing and immunoassays (tumour markers and hormones).
We have long striven — on a voluntary basis — to constantly improve the quality of our facilities. Our laboratory has been accredited by the French Accreditation Committee (COFRAC) [Comité français d’accréditation] for most forms of analysis since 2003, including, since 2017, somatic mutation testing.
More information available at www.cofrac.fr
Nowadays, when lymph node involvement cannot be detected clinically, the sentinel lymph nodes into which breast tumours drain are routinely analysed to check for tumour cells. The sentinel lymph node is the first node in the lymphatic system into which breast tumours drain. They are removed during surgery to remove the tumour. By analysing these nodes, doctors can confirm whether the cancer has spread to the lymph nodes. If tumour cells are found, additional treatment may be required.
We use a fast and sensitive testing technique based on the molecular amplification of cytokeratin-19 (expressed in mammary cells but not in other cells in the lymph nodes) to detect lymph node metastasis.
This technique, known as one-step nucleic acid amplification (OSNA) and marketed by Sysmex, is used to analyse lymph nodes removed during surgery within 30 minutes. Using conventional histological tests, the final results are usually not available until several days after surgery.
As a quantitative, fast, sensitive and standardised technique, OSNA has a number of advantages. In certain cases, thanks to OSNA, surgeons are able to immediately remove axillary lymph nodes that are found to contain tumour cells. Alternatively, it also allows for immediate breast reconstruction once the lymph nodes are confirmed as clear.
Oncologists treating breast cancer patients can now use molecular tests to quantify gene expression in tumours. This helps doctors better understand the risk of disease progression, which allows them to adapt the treatment used, in particular by avoiding chemotherapy if it is not going to be effective.
Doctors change their treatment decisions in response to molecular signatures in around 30% of cases, usually by deescalating the treatment. Each year, some 5000 women in France are able to avoid chemotherapy as a result.
These tests are not required for all patients; they are used only where the clinical and anatomopathological data are not sufficient to formally decide to begin chemotherapy. They are prognostic tests, but cannot predict the response. Prospective studies and complementary assessments are still needed.
The biology department at the Eugène Marquis Centre conducts EndoPredict testing, as developed by Myriad Genetics. Patients with PR-positive/HER2-negative breast cancer are given an EPclin score, which combines the molecular results, the size of the tumour and the number of affected lymph nodes. This score is used to split patients into two groups according to the risk of metastasis after 10 years.
If tumour cells contain the MGMT protein, they will respond less favourably to chemotherapy with alkylating agents, especially temozolomide. MGMT expression is negatively regulated at the level of the DNA via methylation. There is a strong correlation between methylation of the MGMT gene in the tumour and the response to alkylating agents. As part of a French study conducted across multiple institutions, the Centre’s laboratory has helped identify the best techniques for analysing MGMT status in glioblastomas (Quillien et al, Cancer Biomarkers, 2017; Quillien et al, Oncotarget, 2016; Quillien et al, J neurooncol, 2014; Quillien et al, Cancer, 2012).
This test is now routinely carried out for all patients.
Storage of and access to samples is one of the major challenges in research.
Most clinical protocols that study the efficacy of new drugs are accompanied by ancillary studies designed to better understand drugs’ mechanisms of action and/or identify predictive response factors. The Centre’s laboratory helps prepare (from simple centrifugation to more complex preparations involving cellular separation), store and send samples. These pre-analytical processes must be carried out with care in order to ensure good results.
The Eugène Marquis Centre opened a biobank for breast tumours in 2003. It is part of Rennes Biological Resources Centre for Health [Centre de Ressources Biologique (CRB) Santé de Rennes] and has NF S96-900 certification. The aim of the biobank is to ethically collect samples that are subsequently made available for use in research in order to improve understanding and treatment of breast tumours.
In particular, the biobank has supported the research carried out by the research teams at the Centre.