**Role of Microtubule-Associated Protein 1b in Urothelial Carcinoma: Overexpression Predicts Poor Prognosis**

**Tsu-Ming Chien 1,2,3, Ti-Chun Chan 4,5, Steven Kuan-Hua Huang 6, Bi-Wen Yeh 3,5, Wei-Ming Li 1,2,3,7, Chun-Nung Huang 2,3, Ching-Chia Li 1,2,3,8, Wen-Jeng Wu 1,2,3,8,9,10 and Chien-Feng Li 4,5,11,12,13,\***


Received: 6 February 2020; Accepted: 6 March 2020; Published: 9 March 2020

**Abstract:** We sought to examine the relationship between microtubule-associated proteins (MAPs) and the prognosis of urothelial carcinoma by assessing the microtubule bundle formation genes using a reappraisal transcriptome dataset of urothelial carcinoma (GSE31684). The result revealed that microtubule-associated protein 1b (*MAP1B*) is the most significant upregulated gene related to cancer progression. Real-time reverse-transcription polymerase chain reaction was used to measure *MAP1B* transcription levels in urothelial carcinoma of the upper tract (UTUC) and the bladder (UBUC). Immunohistochemistry was conducted to detect *MAP1B* protein expression in 340 UTUC and 295 UBUC cases. Correlations of *MAP1B* expression with clinicopathological status, disease-specific survival, and metastasis-free survival were completed. To assess the oncogenic functions of *MAP1B*, the RTCC1 and J82 cell lines were stably silenced against their endogenous *MAP1B* expression. Study findings indicated that *MAP1B* overexpression was associated with adverse clinical features and could independently predict unfavorable prognostic effects, indicating its theranostic value in urothelial carcinoma.

**Keywords:** urothelial carcinoma; transcriptome; microtubule; MAP1B; prognosis
