miR-34a predicts the prognosis of advanced-stage external auditory canal squamous cell carcinoma

Abstract

Background

External auditory canal (EAC) squamous cell carcinoma (SCC) is a rare disease, and the survival rate is low in the advanced stages. It has been reported that miR-34a expression is low in many cancers and acts as a tumor suppressor, but its function in EACSCC has not yet been reported.

Aims

To analyze the miR-34a expression levels in EACSCC specimens using in situ hybridization (ISH).

Material and Methods

We performed microRNA ISH for miR-34a detection and immunohistochemical analysis of p53 and Ki67 in the EACSCC and otitis externa (OE) specimens.

Results

miR-34a was expressed in the basal and suprabasal layers in the OE epidermis. The pronounced expression of miR-34a was observed in the two cases of T2 (Stage II). In the one case of T3 (Stage III), it was almost the same as that of the OE. On the other hand, the expression levels of miR-34a in the one case of T3 (Stage IV) and two cases of T4 (Stage IV) were apparently reduced.

Conclusion

We demonstrated that the expression level of miR-34a was higher in early-stage EACSCC and lower in advanced-stage EACSCC.

Significance

The expression level of miR-34a may predict a prognosis in patients with advanced-stage EACSCC.

Chinese Abstract

背景：外耳道（EAC）鳞状细胞癌（SCC）是一种罕见的疾病, 晚期生存率低。据报道, miR-34a在很多癌症中的表达较低。它是肿瘤抑制因子, 但关于其在EASCC中的功能尚未报道。

目的：利用原位杂交（ISH）技术分析EASCC标本中miR-34a的表达水平。

材料和方法：我们用microRNA-ISH检测miR-34a并对EASCC和外耳炎（OE）标本中p53和Ki67 进行免疫组化分析。

结果：miR-34a在OE表皮基底层和基底上层均有表达。在两例T2期（II期）患者观察到miR-34a的显著表达。在T3（III期）的一个病例中, miR-34a表达与OE的几乎相同。另一方面, 1例T3（IV or III期）和2例T4（IV期）的miR34a表达水平明显降低。

结论：miR-34a在早期EACSCC中的表达水平较高, 而在晚期EACSCC较低。

意义：miR-34a的表达水平可以预测晚期EACSCC患者的预后。

Keywords:

• miR-34a
• in situ hybridization
• external auditory canal squamous cell carcinoma
• microRNA
• biomarker
• prognosis

Acknowledgments

The authors thank Yukio Nishiya, Masahiro Takahashi, Yukihisa Harayama, Eiji Shimura, Takanori Hama, and Yutaka Yamamoto (Department of Otorhinolaryngology, Jikei University School of Medicine) for the harvesting of the human tissues; Hiroyuki Takahashi (Department of Pathology, Jikei University School of Medicine) for the pathological diagnosis in this work.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by a Grant-in-Aid for Scientific Research from the Japanese Society for the Promotor of Science (JSPS) [nos. JP16K11186 and JP19K09857 to T. Yamamoto-Fukuda, no. JP18K16908 to N. Akiyama].