What is meant by "luminal type" cancer or tumor?

Likely ductal.: Luminal (phenobarbital) anything, like luminal (phenobarbital) cells most likely refers to cells lining a duct, or tube in the body, called a lumen. For example the inside of the gastrointestinal tract is its lumen, lined by epithelial cells. These cells can become cancerous and so they are a luminal (phenobarbital) cancer. Ductal carcinoma of the breast is a better example, as these are cancerous liminal cells of the breast lumen or duct.

Often good prognosis: Molecular biologists can subtype breast cancers in many ways. One classification looks at luminal (phenobarbital) vs. Basaloid cells of origin. Each has specific molecular biology, but luminal (phenobarbital) types tend to have estrogen receptors and basaloid do not. Er+ tumors fare better. The susan g. Komen website explains this well in lay terms. http://ww5.komen.org/breastcancer/subtypesofbreastcancer.html.