Expression of miR-16 is not a suitable reference for analysis of serum microRNAs in melanoma patients

Erica B. Friedman, Shulian Shang, Nathaniel H. Fleming, Eleazar Vega-Saenz de Miera, Eva Hernando, Yongzhao Shao, Iman Osman

Department of Dermatology, New York University, New York, USA.
Division of Biostatistics, New York University, New York, USA.
Interdisciplinary Melanoma Cooperative Group, New York University, New York, USA.

DOI: 10.4236/jbise.2012.511080                

Abstract

Background: The evolving paradigm shift towards the molecular characterization of melanoma has expanded to include studies of microRNA (miRNA) expression. As miR-16 has been utilized as a normalizer in serum-based miRNA studies in several cancers, we evaluated miR-16 expression as a potential reference for normalization of serum miRNA expression in melanoma patients. Methods: 143 primary cutaneous melanoma patients who presented to New York University (NYU) Langone Medical Center for surgical resection of AJCC stage I-III disease were studied. In addition, sera samples from 60 control subjects were utilized including 22 healthy volunteers, 13 rheumatoid arthritis patients, 20 non-melanoma cancer patients (10 renal cell carcinoma and 10 bladder cancer), and 5 Atypical Mole Syndrome patients. The Kruskal-Wallis test (k = 6) or Wilcoxon test (k = 2) with Bonferroni correction was used for analyses of miR-16 expression in melanoma patients compared to various control groups, using raw Ct values directly. The Kruskal-Wallis test was used to compare miR-16 expression across stages of melanoma. The equivalence test for independent samples was used to test the equivalence of miR-16 expression among different groups. Results: No significant differential expression of miR-16 was observed between melanoma patients and healthy volunteers (Wilcoxon test, p = 0.37). However, miR-16 did show a significant difference in expression as it related to stage of melanoma (p = 0.015). Additionally, the equivalence test was unable to confirm equivalent expression of miR-16 in any melanoma versus control group pair. Conclusion: Our data indicate that miR-16 cannot be used as a universal normalizer in sera studies of melanoma patients.

Keywords

MicroRNA; Melanoma; Normalization; Reference Gene

Conflicts of Interest

The authors declare no conflicts of interest.

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