So, adenocarcinoma arises from columnar glandular epithelium.

腺癌来源于柱状上皮腺体细胞。

And then there is the glandular epithelium, which forms glands and secretes hormones and other substances.

然后是腺上皮，形成腺体并分泌激素和其他物质。

On the other hand, adenocarcinoma is the most common type of esophageal cancer in the United States of America, and it originates in the columnar glandular epithelium, most often in the lower third of the esophagus.

另一方面，腺癌是在美国最常见的食管癌类型；腺癌起源于柱状腺上皮细胞，最常位于食管的下三分之一。