Predictive value and molecular correlates of MYC immunohistochemistry and copy number gain in non-small cell lung carcinomas treated with immunotherapy

Objectives

Accurately predicting which patients diagnosed with non-small cell lung cancer (NSCLC) will respond to immunotherapy remains a clinical challenge. This study aims to determine the associations between MYC immunoreactivity, MYC copy number gain (CNG), driver mutations and survival following immunotherapy treatment, to provide insight into whether clinical MYC assessment may have predictive value.

Materials and Methods

MYC copy number status was determined in 82 patients with NSCLC treated with immunotherapy, and MYC immunohistochemistry (IHC) was performed on 80 of these cases. MYC staining in ≥ 40 % of tumor cells was considered positive. Driver gene alterations, PD-L1 status and survival outcomes were assessed through retrospective chart review. Overall survival (OS) and progression free survival (PFS) were calculated from the date of immunotherapy initiation.

Results

Nine (11 %) of 82 cases had MYC CNG and 56 (70 %) of the 80 immunostained cases were positive for MYC. MYC CNG was significantly associated with STK11 mutation (P=0.023), whereas positive MYC IHC was significantly associated with KRAS mutation (P=0.0076) and current/former smoking (P=0.0007). MYC CNG and positive MYC IHC were not significantly associated with each other (P=0.42), or with PD-L1 ≥ 1 % (MYC CNG: P=0.10; MYC IHC: P=0.09). Positive MYC IHC and PD-L1 ≥ 1 % were both significant predictors of OS (MYC: HR 2.7, 95 % CI 1.1–6.4, P=0.026; PD-L1: HR 0.33, 95 % CI 0.15–0.72, P=0.0055). MYC IHC positive/PD-L1 < 1 % cases had the shortest OS (median 230 versus 918 days, P=0.00069) and PFS (median 84 versus 254 days, P=0.0087). MYC CNG was not associated with OS or PFS.

Conclusion

We find that positive MYC IHC is an independent predictor of shorter OS after immunotherapy treatment, with MYC positive/PD-L1 < 1 % status predictive of particularly poor immunotherapy response. We identify positive MYC IHC as a feature of possible relevance to NSCLC treatment selection and of interest for future therapy development.