Aldehyde dehydrogenase 1 (ALDH1), a cancer stem cell marker, has been reported to be altered in human
carcinogenesis. This study assessed the expression of ALDH1
protein in invasive vs. noninvasive
bladder cancer tissues for association with clinicopathological factors and
bladder cancer prognosis. Tissue samples were collected from 227
bladder cancer patients, including 118 with noninvasive and 109 with invasive
bladder cancer for immunostaining of ALDH1 expression. ALDH1 expression in
tumor tissues was significantly greater than that in adjacent normal tissues. ALDH1
protein was highly expressed in 29.07% (66/227) of
bladder tumor tissues (i.e., 24.58% of noninvasive
bladder cancer tissues vs. 33.94% of invasive
bladder cancer tissues). In patients with noninvasive
bladder cancer, ALDH1
protein expression was significantly associated with an advanced
tumor grade and frequent
tumor recurrence (P≤0.05). In patients with invasive
bladder cancer, ALDH1
protein expression was significantly associated with an advanced
tumor grade, stage, as well as lymph node and distant
metastases (P≤0.05). After adjusting for the confounding factors, ALDH1
protein expression was significantly associated with relapse-free survival in noninvasive
bladder cancer patients [HR (95% CI)=4.45 (1.32-15.04); P=0.027] and overall survival in invasive
bladder cancer patients [HR (5% CI)=2.86 (1.72-8.83); P=0.020]. These data indicate that ALDH1 expression plays an important role in
bladder cancer development and prognosis. Further validation of our results is warranted in a larger sample cohort, and further investigation of ALDH1 signaling and function will increase our understanding of ALDH1 in
bladder cancer progression.