While several groups have shown abberant micro-RNA (or miRNA) expression in cancers, a group from Washington University Medical Centre have shown a direct-link of miRNA's as the primary course of a paediatric lung tumor. Pleuropulmonary blastoma (PPB) is an inherited cancer syndrome and the paper in Science by Hill et al. shows a link between the disease and families harbouring a heterozygous mutation in DICER1, the protein responsible for cleaving/processing miRNAs. They propose that loss of DICER1 expression in the epithelial tissue of the tumour alters proliferation of the surrounding mesenchymal tissue. This is the first paper showing a direct causal link between miRNA's and an associated cancer.

It is not unusual for the disease to be a result of a heterozygous mutation, as in the animal model a deletion of DICER1 is lethal due to the role miRNAs play during natural development. It is expected that DICER1 plays a similar in human development, and abberant DICER1 expression in a paediatric cancer is fitting with the hypothesised role for the protein.

Original article:

DICER1 Mutations in Familial Pleuropulmonary Blastoma

D. Ashley Hill ^1*, J. Ivanovich ², John R. Priest ³, Christina A. Gurnett ², Louis P. Dehner ², David Desruisseau ², Jason A. Jarzembowski ⁴, Kathryn A. Wikenheiser-Brokamp ⁵, Brian K. Suarez ², Alison J. Whelan ², Gretchen Williams ⁶, Dawn Bracamontes ¹, Yoav Messinger ⁶, Paul J. Goodfellow ²

Published Online June 25, 2009
Science DOI: 10.1126/science.1174334

https://www.researchgate.net/publication/26320744_DICER1_Mutations_in_Familial_Pleuropulmonary_Blastoma