The YPEL5–PPP1CB fusion transcript is detected in different hematological malignancies and in normal samples

• YPEL5–PPP1CB is a chimeric transcript detected in CLL.
• We detect this transcript also in non-CLL samples.
• This marker is not suitable for diagnostic purposes of CLL.

Chronic lymphocytic leukemia (CLL) is the most frequent leukemia in Western adults. It was suggested that transcripts from a reciprocal trans-splicing event between YPEL5 and PPP1CB were present exclusively in CLL patients (more than 90%). Here we show that the YPEL5–PPP1CB fusion is not specific for CLL but is also detected in other hematological malignancies such as chronic myeloid leukemia, monoclonal B cell lymphocytosis or acute leukemia and also in normal samples. As such, it is unlikely that the YPEL5–PPP1CB fusion is a good drug target in CLL or a suitable target to monitor disease.