Invasive ductal carcinoma ex pleomorphic adenoma of the lacrimal gland - a long term follow-up case

We experienced a case of malignant orbital tumor in a 72-year-old Japanese man. He noticed protrusion of his left eye, and received resection of the left orbital tumor. The tumor contained several different components such as high-grade invasive ductal carcinoma, low-grade/minimally invasive adenocarcinoma and pleomorphic adenoma. Pathological diagnosis of high-grade invasive ductal carcinoma ex pleomorphic adenoma of the left lacrimal gland was made. He had undergone surgical removal of the left lacrimal gland tumor at the other hospital 19 years before, and the surgical specimen revealed that most part of the tumor was pleomorphic adenoma but low-grade/minimally invasive adenocarcinoma was included as a minor component (low-grade/minimally invasive adenocarcinoma ex pleomorphic adenoma). Thus, we could observe the natural course of low-grade/minimally invasive adenocarcinoma ex pleomorphic adenoma which transformed into high-grade invasive ductal carcinoma ex pleomorphic adenoma. Lacrimal gland ductal carcinoma is an extremely rare tumor, and only 25 cases have been reported before in English literature. Moreover, our case is the 5th case of lacrimal gland ductal carcinoma ex pleomorphic adenoma. Keywords: Lacrimal gland, Carcinoma ex pleomorphic adenoma, Androgen receptor, HER

Signal-anchor sequences are an essential factor for the Golgi-plasma membrane localization of type II membrane proteins

<p>Despite studies of the mechanism underlying the intracellular localization of membrane proteins, the specific mechanisms by which each membrane protein localizes to the endoplasmic reticulum, Golgi apparatus, and plasma membrane in the secretory pathway are unclear. In this study, a discriminant analysis of endoplasmic reticulum, Golgi apparatus and plasma membrane-localized type II membrane proteins was performed using a position-specific scoring matrix derived from the amino acid propensity of the sequences around signal-anchors. The possibility that the sequence around the signal-anchor is a factor for identifying each localization group was evaluated. The discrimination accuracy between the Golgi apparatus and plasma membrane-localized type II membrane proteins was as high as 90%, indicating that, in addition to other factors, the sequence around signal-anchor is an essential component of the selection mechanism for the Golgi and plasma membrane localization. These results may improve the use of membrane proteins for drug delivery and therapeutic applications.</p> <p>The sequence around the signal-anchor is an essential component of the selection mechanism for Golgi and plasma membrane protein localization.</p