Abstract
Monoamine oxidases (MAOs) including MAOA and MAOB are enzymes located on the outer membranes of mitochondria, which are responsible for catalyzing monoamine oxidation. Recently, increased level of MAOs were shown in several cancer types. However, possible roles of MAOs have not yet been elucidated in the progression and prognosis of colorectal carcinoma (CRC). We therefore analyzed the importance of MAOs in CRC by an in silico analysis and tissue microarrays. Several independent cohorts indicated that high expression of MAOB, but not MAOA, was correlated with a worse disease stage and poorer survival. In total, 203 colorectal adenocarcinoma cases underwent immunohistochemical staining of MAOs, and associations with clinicopathological parameters and patient outcomes were evaluated. We found that MAOB is highly expressed in CRC tissues compared to normal colorectal tissues, and its expression was significantly correlated with a higher recurrence rate and a poor prognosis. Moreover, according to the univariate and multivariate analyses, we found that MAOB could be an independent prognostic factor for overall survival and disease-free survival, and its prognostic value was better than T and N stage. Furthermore, significant positive and negative correlations of MAOB with mesenchymal-type and epithelial-type gene expressions were observed in CRC tissues. According to the highlighted characteristics of MAOB in CRC, MAOB can be used as a novel indicator to predict the progression and prognosis of CRC patients.
Highlights
Colorectal cancer (CRC) is one of the most common cancers among all races [1]
We stratified our recruited CRC patients into subgroups according to the pathological stage, and results indicated that high MAOB expression remained significantly correlated with a poor prognosis in patients with late stage (Figure S1A, lower panel)
Clinical applications according to biomarker functions can be separated into diagnostic, predictive, or pCrolginniocastlicabpipolmicaartkioenrss
Summary
Colorectal cancer (CRC) is one of the most common cancers among all races [1]. The incidence of CRC has rapidly increased in Asian countries during the last decade [2]. Our results from TMAs showed that a high MAOB expression level was observed in CRC tissue and positively correlated with a higher recurrence. .2001240), 2(F1,igx;udroei:2FCO,DR )P.ETEhReRMEVAIEOWA expression level was not associated with these two surviva4l of 4 probabilities (p = 0.463 and 0.818, respectively) (Figure 2E,F) According to these in silico analyses, thheisgeheinr MsilAicOoBa,nbaulytsneost, MhigAhOeAr M, exApOreBs,sbiount mnoigt hMt AbeOaAp,oeoxrpprreosgsinoonstmicimghatrkbeerainpoCoRrCp.rognostic marker in CRC. M0 M1 TNM stage Stage I Stage II Stage III Stage IV Grade Grade 1 Grade 2 Grade 3 NA Adjuvant chemotherapy No Yes Vascular invasion No Yes Perineural invasion No Yes Tumor histology Non-mucinous Mucinous Recurrence No Yes n MAOA Expression, n (%) p MAOB Expression, n (%) p-Value.
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