In parallel, we evaluated the matched gene RNA transcript levels (Log2 normalized transcripts per million, TPM) within the context of a cohort of HNSCC and lung cancer (figure 1B).25 For the primary tumor, TPM for CD3D, CD4 and CD8A, PD-1 and PD-L1 fell in the bottom tertile of the cohort, consistent with IHC data. Here, CD4 is linked to lung carcinoma.