Observational, multicentre, retrospective study on patients taken care according to the national guidelines. The objective is to define, after the diagnosis confirmation, the frequency of PD-L1 expression in patients with large-cell lung neuroendocrine carcinoma (NEC), whatever the stage of the disease, and to correlate this parameter to clinical data at the time of diagnosis, therapeutic response and survival. Large-cell NECs present a bad prognostic and there is no evidence of treatment for these patients with advanced disease in second ligne of treatment at that time. To demonstrate the PD-L1 expression in this type of cancer might have a major therapeutic impact in a close future to access immunotherapies.

Inclusion Criteria:

• Patients aged > or = 18 years
• Diagnosis of Large-cell NEC confirmed by centralised reading
• Tumoral materials available and readable for PD-L1 labeling

Exclusion Criteria:

• Other type of Lung cancers
• Tumoral material not available or not readable for centralised reading
• Tumoral material not available or not readable for PD-L1 labeling

Patients presenting a large-cell NEC taken in charge by investigational centres between January 1st, 2014 and December 31st, 2016.

Alive patients will be identified during disease follow-up visit as per the local current practice and the study will be then proposed to them at that time.

For died patients, eligible patients will be identified by checking the files present at site by the Principal Investigator.