The loss of 198 nucleotides in CPE exon1 through intra-exonic splicing suggests the way 40kDa CPE-ΔN is generated in human cancer cells differs from its counterpart in the mouse, the latter uses a different transcription starting site to create the 40kDa CPE-ΔN and not through alternative splicing, and only appears to be expressed in embryos [22]. This evidence concerns the gene CPE and cancer.