Long non-coding RNAs (lncRNA) which are longer than 200 base pairs in length, play an important role in cellular machinery. Chronic lymphocytic leukemia (CLL) and multiple myeloma (MM) are neoplasms of B-cells. In our study we aimed to investigate circulating lncRNA levels of CLL and MM patients. For this purpose we selected 5 candidate lncRNAs (TUG1, LincRNA-p21, MALAT1, HOTAIR, and GAS5) where the first two are regulated by p53. Analyses were performed by real-time PCR using cDNA synthesized from plasma RNAs. In both disease groups differential levels of plasma lncRNAs were observed. LincRNA-p21 was the only molecule displaying significant changes in the CLL group while all remaining lncRNAs showed significant differences in the MM group. In the MM group only TUG1 showed higher levels than the healthy volunteers. In conclusion, the expression levels of the candidate lncRNA molecules display a general trend for tissue- and disease-specific expression which can provide important potential biomarkers specific to the particular disease type. However, further studies are necessary to elucidate their involvement in disease development and progression. (C) 2014 Elsevier B.V. All rights reserved.