EGR1 and gastric cancer: Cluster C2 showed high expression of the transcription factors EGR1 and JUNB and transcriptional regulator NUPR1, whereas cluster C4 contained cells expressing high levels of heat shock protein (HSP)-encoding genes, such as HSPA1A and HSPA6 (HSP70 family), which are known to be involved in the pathology of gastric cancer (Figure 2E and Supplemental Figure S1) [42].