Paraneoplastic neurological syndromes (PNS) are immune-mediated complications of cancer that can affect any part of the central or peripheral nervous system.

PNS occurs at the intersection between immune system and the tumor, where a combination of genetical and environmental factors may play a role.

Mechanisms leading to immune tolerance breakdown and autoimmunity in PNS remain largely unknown, and this reflects in an unsatisfactory repertoire of treatments available. Moreover, a better understanding of the biological mechanisms underlying PNS would allow a more precise identification of the modalities that permit PNS patients to have a better oncological prognosis than cancer patient without PNS, with obvious repercussions in clinical oncology.

To this effect, an extremely innovative approach involves directly exploring the tumoral tissue of patients suffering from specific PNS via genomic and transcriptomic analysis.

The study team hypothesizes that antigen ectopic expression by tumour cells may contribute to the generation of PNS.

In the present study, the investigators will analyze the salient features of tumors associated with PNS, namely the histological and immune cells infiltrate characteristics, their transcriptomic profile, and mutational status of involved antigens.

Inclusion Criteria:

• presence of well characterized antibodies in serum or cerebrospinal fluid;
• histologically proven cancer with available tumour sample;
• Paraneoplastic neurological syndrome (PNS) diagnosis according to the international guidelines;
• Age: at least 18 years old.

Exclusion Criteria:

• Absence of complete clinicopathological data

Patients with cancer and suspected Paraneoplastic neurological syndrome (PNS) whose sample was sent for analysis at the Centre de référence des syndromes neurologiques paranéoplasiques et encéphalites auto-immunes, Lyon, France, for paraneoplastic antibody study and then stored at the biobank Neurobiotec.