Satellite Noncoding RNAs (ncRNA) as Cancer Biomarkers? New Insights from <i>FA-SAT</i> ncRNA Molecular and Clinical Profiles in Feline Mammary Tumors.

Satellite noncoding RNAs (ncRNAs) are a new frontier of cancer biology research and biomarkers. While the knowledge on ncRNAs in human cancers is still limited, studies in other species can be informative to guide future translational research and development for cancer molecular targets and diagnostics. In this context, <i>FA-SAT</i> is the major satellite DNA of the cat genome, which is also present in humans, being transcribed in both species. In this study, we report new insights on <i>FA-SAT</i> (DNA and RNA) profile in feline mammary tumors, using disease-free tissues from the same animals as reference. We quantified the <i>FA-SAT</i> DNA and RNA levels (long and small transcripts) by real-time quantitative polymerase chain reaction (qPCR) and RT-qPCR. The comparison of the <i>FA-SAT</i> DNA and RNA levels with clinicopathological parameters revealed several associations, such as (1) the <i>FA-SAT</i> DNA levels' positive relation with lymphovascular invasion, (2) the <i>FA-SAT</i> long RNA negative correlation with Ki-67 index, and its positive association with Estrogen Receptor status, and (3) the <i>FA-SAT</i> small RNA level positive correlation with tumor size and skin ulceration. Also, <i>FA-SAT</i> long RNA is correlated with <i>ERBB2</i> and <i>c-MYC</i> RNA levels. These data collectively suggest that <i>FA-SAT</i> ncRNA offers prospects as a potential cancer biomarker in cats. Further studies in humans are also needed to decipher the emerging role of ncRNAs in cancer biology and precision medicine fields. This work brings new information on the relation of <i>FA-SAT</i> ncRNAs with the oncogenic process, uncovering a new potential cancer biomarker.