Laurence BAGUR MISTRE

Trained as a laboratory technician, I joined  the pathology laboratory at Hôpital Nord  16 years ago, where I specialized in immunolabeling techniques and am today in charge of histopathology processing for The PIONeeR Project.

To summarize sample processing at our service, we typically receive either a biopsy or a surgical resection that we dehydrate before embedding in paraffin blocks. The embedded tissue is sectioned into slices of 3 to 4 µm and mounted on glass slides. A subset of these slides is used for HPS staining – a technique that uses a combination of three stains, hematoxylin, phloxine and saffron, to reveals the histology of a sample – and is analyzed by pathologists within the service to establish a diagnosis. Other slides are used for complementary analyses, including immunolabeling, immunofluorescence and various molecular biology techniques.

Histopathological analyses are critical to establish a diagnosis based on microscopic tissue examination, but are also of great importance in the context of medical research protocols, for example to identify biomarkers that would predict response to a given treatment. In the case of the PIONeeR Project, we are confronted with one challenge, which is that we need to be able to prepare at least 22 slides from each patient biopsy in order to complete the full panel of biomarker analyses dictated by the project’s protocol. Among the 22 slides, 3 are used for HPS staining to assess the histology of the sample throughout the sections, and 1 is used to reveal PD-L1 and CD8 proteins by immunolabeling. The rest of the slides are sent off to HalioDx to explore the potential of new biomarkers of response to immunotherapy in lung cancer patients.