Tissue expression of miR-449a as risk factor for occult neck metastasis in patients with cT3-T4 N0 laryngeal cancer. A pilot study.

Objective: To explore the potential role of miR-449a as biomarker for laryngeal squamous cell carcinoma (LSCC), especially in the decision strategy of neck dissection (ND).

Methods: Each patient underwent total laryngectomy and bilateral ND (levels II-IV); during surgery, tissue samples of around 1 × 0.5 cm were extracted from both healthy tissue adjacent to the tumor and the visibly affected tumor tissue. The extraction of total RNA, encompassing miRNA, was performed using a mirVana PARIS kit. To detect miR449a, cDNA was synthesized from 200 ng of RNA using a TaqMan miRNA reverse transcription kit.

Results: The study group was formed of 66 patients (62 males, and 4 females) with LSCC, aged between 39 and 77 years (mean 60 + 14.56 yr). MiR-449a was up-regulated in twenty-eight tumors (42%), while it was down-regulated in 38 samples (58%). In the present study, there was a statistical relevance for miR-449a tissue expression for pN staging (p = 0.017), and PNI (p = 0.005). Eight tumors (12%) cN0 became pN + showing occult cervical lymph node metastases at the final histopathological examination, and all of these patients showed miR-449a downregulation.

Conclusion: Super-selective ND (sparing the sub evels IIb and IV) might be the approach to cT3-T4 N0 LSCCs with upregulation of miR-449a; on the other hand, to ensure and effective control of occult neck metastases it would be appropriate to reserve elective ND (including sublevels IIb and IV) for cT3-T4 N0 LSCCs with miR-449a downregulation. Although promising, due to the small size of the cohort, the results of this work can be considered preliminary and need to be confirmed by prospective and larger studies.