Paired cisternae in human tumor cells

Abstract

An unusual arrangement of cisternae, described as “paired cisternae of endoplasmic reticulum” or “stacked remnants of nuclear envelope” was observed in various human tumor cells in vivo. Paired cisternae appeared to arise from nuclear envelope remnants of rapidly dividing cells and eventually to separate into individual cisterna of endoplasmic reticulum. The terms “paired cisternae of endoplasmic reticulum” and “stacked remnants of nuclear envelope,” by which this structure is referred to in the literature, probably apply to the same structure, differing only in stage of development. The present study supports the concept that nuclear envelope is a source of endoplasmic reticulum.