Acquired ribosomopathies in leukemia and solid tumors

A mutation in the gene encoding the small subunit-associated ribosomal protein RPS19, leading to RPS19 haploinsufficiency, is one of the ribosomal protein gene defects responsible for the rare inherited bone marrow failure syndrome Diamond Blackfan anemia (DBA). Additional inherited and acquired defects in ribosomal proteins (RPs) continue to be identified and are the basis for a new class of diseases called the ribosomopathies. Acquired RPS14 haploinsufficiency has been found to be causative of the bone marrow failure found in 5q- myelodysplastic syndromes. Both under- and overexpression of RPs have also been implicated in several malignancies. This review will describe the somatic ribosomopathies that have been found to be associated with a variety of solid tumors as well as leukemia and will review cancers in which over- or underexpression of these proteins seem to be associated with outcome.

RPL36 as a prognostic marker in hepatocellular carcinoma

Ribosomal proteins (RP) play key roles in the regulation of apoptosis, multidrug resistance and carcinogenesis. The aim of this study was to investigate the expression of ribosomal protein L36 (RPL36) in hepatocellular carcinoma (HCC) and to correlate it with clinicopathological parameters and clinical outcome. Liver specimens were obtained from 60 HCC patients who had undergone a partial hepatectomy. Expression of RPL36 in tumor tissue and surrounding non-tumorous tissues was evaluated on a tissue microarray by immunohistochemistry. RPL36 was expressed in 45 of 60 (75%) HCC by immunohistochemistry, but was not detected in corresponding non-tumors. RPL36 expression correlated significantly with serum levels of albumin (P= 0.044) and prothrombin time (P= 0.026), which reflect liver synthetic function. Moreover, expression of RPL36 was found to be higher in patients with early tumor stages (I/II) (P= 0.038) or without portal vein thrombosis (P= 0.005). In univariate analysis, patients with RPL36 expression revealed better overall survival (P= 0.037). By multivariate survival analysis, RPL36 expression was found to be an independent prognostic factor for overall survival (P= 0.026). Our data suggest that RPL36 may be involved in the early stage of hepatocarcinogenesis, and it can be used as an independent and potential prognostic marker for resected HCC.