The purpose of the study is to determine in brain metastases and according to feasibility in liquid biopsies:

• Molecular alterations including in particular mutations, amplifications, Copy number gene variants and fusion transcripts identified by high-throughput sequencing;
• The rate of variation either in gain or in loss of expression of the different messenger Ribonucleic Acids by analysis of the transcriptome;
• Epigenetic alterations by methylation of deoxyribonucleic acid clusters by methylome chips.

This is a single-center, prospective, interventional, exploratory study aimed at comparing the molecular alteration profile of liquid biopsies (blood and lumbar puncture) to that of brain metastases.

The population eligible for the study will consist of any patient with cerebral metastases from a solid cancer, at least one of which is accessible to surgical excision.

The study consists of comparing, between brain metastases and liquid biopsies (blood and lumbar puncture), the profiles of genomic, post-genomic and epigenetic alterations as well as the mutational load. To do this, the study only requires a lumbar puncture and a blood test.

Inclusion Criteria:

• Patient aged 18 or over;
• Patient with cerebral metastases from a solid cancer, at least one of which is accessible to surgical excision (contrast enhancement of at least 1 cm);
• Patient able to understand the information related to the study and to read the information leaflet;
• Patient having signed a written informed consent to participate in the study.

Exclusion Criteria:

• Patient with a medical contraindication to surgery and anesthesia;
• Patient whose anatomical location of the cerebral metastasis contraindicates wide resection;
• Patient with a contraindication to performing a lumbar puncture;
• Pregnant, parturient or breastfeeding women;
• Patient participating in another clinical trial, or in a period of exclusion from another clinical trial;
• Patient under guardianship or curatorship, or under a regime of deprivation of liberty;
• Patient not benefiting from a social security scheme.