Endoscopic diagnosis and treatment of esophageal verrucous squamous cell cancer.

Verrucous squamous cell cancer (VSCC) of the esophagus is a variant of squamous cell carcinoma. This rare entity has been described in only a handful of case reports in the literature. We sought to evaluate the endoscopic features, treatment, and outcomes related to esophageal VSCC. The medical records of all patients with esophageal VSCC seen at our institution from January 1995 to December 2010 were reviewed retrospectively. A total of 11 patients (6 men; mean age 66 years [range 57-75 years]) were identified, with a mean follow up of 4 years (range 0.5-10 years) available in nine patients after diagnosis. About half the patients smoked or consumed alcohol on a regular basis. The median time interval from onset of symptoms to diagnosis of esophageal VSCC was 2.5 years (range 1-20 years), with dysphagia being present in all patients. The majority of tumors (8 of 11) exhibited a white, warty, plaque-like appearance with superimposed Candida at endoscopy, which led solely to a diagnosis of Candida esophagitis on initial presentation. The disease was either extensive (n = 5) throughout the esophagus or localized (n = 6) often by tumor nodules or projections, with the lower third of the esophagus being most commonly involved. Initial pinch biopsies were nondiagnostic in eight (73%) of the patients. Six patients underwent esophagectomy; neoadjuvant chemoradiation therapy was provided in two. In patients treated solely with surgery and who had a preoperative endoscopic ultrasound, the latter tended to overestimate staging of the lesion relative to surgical pathologic staging. Two patients were deemed to be poor operative candidates and received only chemoradiation treatment. One patient with a T2N0 tumor by endoscopic ultrasound staging was managed symptomatically with intermittent endoscopic dilation because of significant comorbidities that precluded surgery and oncologic therapy. There has been no evidence for residual or recurrent neoplastic disease in the eight patients who received treatment with surgery and/or chemoradiation therapy. Five of six patients who underwent surgery have required intermittent endoscopic dilation of anastomotic strictures during follow up. One of the two patients who received only chemoradiation therapy has required periodic endoscopic dilation for radiation-induced esophageal stricture. Two of the nine (22%) patients have died of causes unrelated to VSCC or its treatment at last follow up. In conclusion, a high index of suspicion for esophageal VSCC should be raised by the presence of long-standing symptoms coupled with white, warty esophageal lesions seen on endoscopic evaluation. Candida overgrowth can be expected to confound the diagnosis. Despite the long duration of symptoms, surgical resection typically shows relatively low-grade tumors, consistent with the rare propensity of this variant of esophageal squamous cell carcinoma to metastasize.

Evidence for a cholesterol transport pathway from lysosomes to endoplasmic reticulum that is independent of the plasma membrane.

We have studied the movement of low density lipoprotein (LDL)-derived cholesterol in cultured Chinese hamster ovary cells. Our hypothesis is that when LDL cholesterol is effluxed from lysosomes, the bulk of LDL cholesterol is mobilized to the plasma membrane, while another pathway delivers LDL cholesterol from lysosomes to acyl-CoA/cholesterol acyltransferase (ACAT) in the endoplasmic reticulum. Three lines of evidence support this model. First, LDL cholesterol transport to ACAT can be blocked without inhibiting the movement of cholesterol from lysosomes to plasma membrane or from plasma membrane to endoplasmic reticulum. Second, LDL cholesterol transport to ACAT is normal in a Chinese hamster ovary mutant with defective plasma membrane-to-ACAT movement. Third, LDL cholesterol is not diluted by the plasma membrane cholesterol pool before reaching ACAT. Our evidence supports a vesicular model of cholesterol transport from lysosomes to the endoplasmic reticulum that is independent of the plasma membrane.

Analysis of a Chinese hamster ovary cell mutant with defective mobilization of cholesterol from the plasma membrane to the endoplasmic reticulum.

The factors involved in shuttling cholesterol among cellular membranes have not been defined. Using amphotericin B selection, we previously isolated Chinese hamster ovary cell mutants expressing defects in intracellular cholesterol transport. Complementation analysis among seven mutants identified one cell line, mutant 3-6, with a unique defect. The present analysis revealed three key features of mutant 3-6. First, the movement of cholesterol both from the endoplasmic reticulum and through lysosomes to the plasma membrane was normal. However, when intact 3-6 cells were treated with sphingomyelinase, movement of plasma membrane cholesterol to acyl CoA:cholesterol acyltransferase in the endoplasmic reticulum was defective. Cellular cholesterol was mobilized to this enzyme upon activation by 25-hydroxycholesterol. Second, mutant 3-6 did not utilize endogenously synthesized sterol or low density lipoprotein-derived cholesterol for growth as effectively as parental Chinese hamster ovary cells. Finally, despite normal movement of cholesterol to the plasma membrane, mutant 3-6 was amphotericin B resistant. The plasma membrane cholesterol content was normal as assessed by cholesterol oxidase treatment and Semliki Forest virus fusion, which suggests that the 3-6 mutation alters the organization of cholesterol in the plasma membrane. Our characterization of this mutant cell line should facilitate the identification of gene(s) required for this transport pathway.