PBK and pancreatic insulinoma: Next, to elucidate the relationship between upregulated Pbk expression and beta cell proliferation, we showed that shRNA‐mediated Pbk knockdown (KD) suppressed growth of INS‐1 cells, a rat insulinoma‐derived cell line (Fig 1L), whereas ectopic expression of Pbk promoted INS‐1 cell growth (Fig 1M).