CD274 and neoplasm: Figure 6B and C illustrate examples of PAGES-HBC genes that showed transient expression changes in the post-trastuzumab tumor. We also evaluated changes in the expression of PDCD1 (PD-1) and CD274 (PD-L1) in the longitudinal samples and found that both genes were highly expressed in the post-trastuzumab tumor, but relatively low in the primary and metastatic recurrent tumors (Figure 6D).