In addition to the major DNA methyltransferases, DNMT1 (Figure 2B), DNMT3A (Figure 2C) and DNMT3B (Figure 2D) and the S-Adenosylmethionine synthetase (MAT2A; Figure 2E) which creates S-adenosylmethionine (SAM) which is critical for methylation processes, we also found SUV39H1 (Figure 2F) to be differentially expressed between the four SCLC subtypes, especially between neuroendocrine and non-neuroendocrine subtypes. This evidence concerns the gene DNMT3A and small cell lung carcinoma.