Because PTB plays a pivotal role in the alternative splicing of multiple genes, including some genes involved in the proliferation of tumour cells, such as pyruvate kinase, ubiquitin-specific protease 5 (USP5) and reticulon-4 (RTN4), we analysed changes in the expression of different alternative splicing isoforms of these genes after PTB knockdown. This evidence concerns the gene USP5 and neoplasm.