ABSTRACTy-Glutamyl transpeptidase (GGT) is an ectoenzyme that catalyzes the first step in the cleavage of glutathione (GSH) and plays an essential role in the metabolism of GSH and GSH conjugates of carcinogens, toxins, and eicosanoids. To learn more about the role of GGT in metabolism in vivo, we used embryonic stem cell technology to generate GGT-deficient (GGTml/GGTml) mice. GGTdeficient mice appear normal at birth but grow slowly and by 6 weeks are about half the weight of wild-type mice. They are sexually immature, develop cataracts, and have coats with a gray cast. Most die between 10 and 18 weeks. Plasma and urine GSH levels in the GGTml/GGTml mice are elevated 6-fold and 2500-fold, respectively, compared with wild-type mice. Tissue GSH levels are markedly reduced in eye, liver, and pancreas.Plasma cyst(e)ine levels in GGTm'/GGTml mice are reduced to '20% of wild-type mice. Oral administration of Nacetylcysteine to GGTml/GGTml mice results in normal growth rates and partially restores the normal agouti coat color. These findings demonstrate the importance of GGT and the y-glutamyl cycle in cysteine and GSH homeostasis.

Aim: To evaluate the effect of topically administered bevacizumab (Avastin) on experimental corneal neovascularisation in rats. Methods: Silver nitrate sticks (75% silver nitrate, 25% potassium nitrate) were used to perform chemical cauterisation on the corneas of 16 eyes from 16 male Long Evans rats. For the following 7 days, the 10 eyes in the treatment group were instilled with bevacizumab 4 mg/ml drops twice daily, whereas the 6 eyes in the control group received placebo (normal saline drops twice daily). Digital photographs of the cornea were analysed to determine the area of cornea covered by neovascularisation as a percentage of the total corneal area. Results: In the bevacizumab-treated eyes, neovascularisation covered, on average, 38.2% (15.5%) (mean (SD)) of the corneal surface compared with 63.5% (5.0%) in the control group (p,0.02, Mann-Whitney U test). Conclusion: Topically administered bevacizumab (Avastin) at a concentration of 4 mg/ml limits corneal neovascularisation following chemical injury in the male Long Evans rat model.

After completing this course, the reader will be able to:1. Discuss the need for a multidisciplinary approach to the management of children with retinoblastoma.2. Identify the patient factors that need to be considered when choosing the most appropriate initial and subsequent treatment for a child with retinoblastoma.3. Describe the role of genetics in the follow-up of retinoblastoma patients.Access and take the CME test online and receive 1 AMA PRA Category 1 Credit ™ at CME.TheOncologist.com CME CME ABSTRACTThe most common ocular cancer in children is retinoblastoma. It affects approximately 300 children in the U.S. every year. It can affect one or both eyes and the disease can be inherited. Altered discoloration of the pupil and strabismus are the usual symptoms that lead to medical attention. Subsequent appropriate diagnostic studies and care provided by a multidisciplinary team, including an ophthalmologist, a pediatric oncologist, a radiation oncologist, and a geneticist, among others, often result in optimal short-term and long-term care. The best initial and subsequent treatments are based on whether the child has unilateral or bilateral disease, the stage of the disease, and the age of the child. Enucleation, chemotherapy, and various forms of radiation therapy along with local ophthalmic therapies can be used in the treatment of retinoblastoma. Cure rates are high in children when the tumor is confined to the eye and has not spread systemically or into the orbit or brain. Children with the heritable form of retinoblastoma are at high risk for developing subsequent malignancies, most commonly sarcomas. This risk is greater for those children with the heritable form of the disease who were exposed to ionizing radiation at age <1 year. Exciting discoveries using animal models are providing new insights into the development of this disease and opening new avenues for targeted therapies that may lead to high cure rates with minimal toxicities. EPIDEMIOLOGYRetinoblastoma is the most common malignant ocular tumor in childhood and affects approximately 1 in 18,000 children Ͻ5 years of age in the U.S. [1]. The incidence is higher in developing countries, and in some countries in Central and South America retinoblastoma is one of the most common solid tumor malignancies in children [2]. The reason for this higher incidence is not clear. Lower socioeconomic status and the presence of human papilloma virus sequences in the retinoblastoma tissue have been implicated [3]. A higher risk for diseases like retinoblastoma in children born through in vitro fertilization was described previously, but a recent large study does not support this association [4]. Approximately 80% of children with retinoblastoma are diagnosed before 3 years of age. The diagnosis of retinoblastoma in children 6 years or older is extremely rare. Children with bilateral retinoblastoma constitute about 20%-30%. Patients with bilateral disease usually present at a younger age (14 -16 months) than patients with unilateral disease (29 -30 months) [...

Tumor-derived cell-free DNA (cfDNA) has biomarker potential; therefore, this study aimed to identify cfDNA in the aqueous humor (AH) of retinoblastoma eyes and correlate somatic chromosomal copy-number alterations (SCNA) with clinical outcomes, specifically eye salvage. AH was extracted via paracentesis during intravitreal injection of chemotherapy or enucleation. Shallow whole-genome sequencing was performed using isolated cfDNA to assess for highly recurrent SCNAs in retinoblastoma including gain of 1q, 2p, 6p, loss of 13q, 16q, and focal amplification. Sixty-three clinical specimens of AH from 29 eyes of 26 patients were evaluated; 13 eyes were enucleated and 16 were salvaged (e.g., saved). The presence of detectable SCNAs was 92% in enucleated eyes versus 38% in salvaged eyes ( = 0.006). Gain of chromosome 6p was the most common SCNA found in 77% of enucleated eyes, compared with 25% of salvaged eyes ( = 0.0092), and associated with a 10-fold increased odds of enucleation (OR, 10; 95% CI, 1.8-55.6). The median amplitude of 6p gain was 1.47 in enucleated versus 1.07 in salvaged eyes ( = 0.001). The presence of AH SCNAs was correlated retrospectively with eye salvage. The probability of ocular salvage was higher in eyes without detectable SCNAs in the AH ( = 0.0028), specifically 6p gain. This is the first study to correlate clinical outcomes with SCNAs in the AH from retinoblastoma eyes, as such these findings indicate that 6p gain in the aqueous humor is a potential prognostic biomarker for poor clinical response to therapy. The correlation of clinical outcomes and SCNAs in the AH identified in the current study requires prospective studies to validate these finding before SCNAs, like 6p gain, can be used to predict clinical outcomes at diagnosis. .

AdV-TK followed by ganciclovir can be administered safely to children with retinoblastoma. Suicide gene therapy may contribute to the treatment of children with retinoblastoma tumor seeds in the vitreous, a resistant complication of retinoblastoma.

Endocrine mucin-producing sweat gland carcinoma (EMPSGC) is a rare, low-grade adnexal neoplasm with predilection for the periorbital skin of older women. Histologically and immunophenotypically, EMPSGC is analogous to another neoplasm with neuroendocrine differentiation, solid papillary carcinoma of the breast. Both lesions are spatially associated with neuroendocrine mucinous adenocarcinomas of the skin and breast, respectively. EMPSGC is ostensibly a precursor of neuroendocrine-type mucinous sweat gland adenocarcinoma (MSC), a lesion of uncertain prognosis. Non-neuroendocrine MSC has been deemed locally aggressive with metastatic potential, and previous works speculated that EMPSGC-associated (neuroendocrine-type) MSC had similar recurrence and metastatic potential with implications for patient follow-up. Only 96 cases of EMPSGC have been reported (12 cases in the largest case series). Herein, we present 63 cases diagnosed as “EMPSGC” in comparison with aggregated results from known published EMPSGC cases. We aim to clarify the clinicopathologic features and prognostic significance of the neuroendocrine differentiation of EMPSGC and its associated adenocarcinoma and to determine the nosological relevance of EMPSGC association in the spectrum of MSC histopathogenesis. Results established an overall female predominance (66.7%) and average presenting age of 64 years. EMPSGC lesions were associated with adjacent MSC in 33.3% of cases. The recurrence rate for neuroendocrine-type MSC was ~21%, less than the reported 30% for non-neuroendocrine MSC. There were no cases of metastasis. EMPSGC and neuroendocrine-type MSC are distinct entities with more indolent behavior than previously reported, supporting a favorable prognosis for patients.

Retinoblastoma is curable when diagnosed early and treated appropriately; however, the prognosis is dismal when the basic elements in diagnosis and treatment are lacking. In developing countries, poor education, lower socioeconomic conditions, and inefficient health care systems result in delayed diagnosis and suboptimal care. Furthermore, the complexity of multidisciplinary care required is seldom possible. While ocular salvage is a priority in the Western world, death from retinoblastoma is still a major problem in developing countries. To bring the two ends of this spectrum together and provide a forum for discussion, the One World, One Vision symposium was organized, where clinicians and researchers from various cultural, geographic, and socioeconomic backgrounds converged to discuss their experiences. Strategies for early diagnosis in developing countries were discussed. Elements in the development of retinoblastoma centers in developing countries were discussed, and examples of successful programs were highlighted. An important component in this process is twinning between centers in developing countries and mentor institutions in high-income countries. Global initiatives by nongovernmental organizations such as the International Network for Cancer Treatment and Research, Orbis International, and the International Agency for Prevention of Blindness were presented. Treatment of retinoblastoma in developing countries remains a challenge. However, it is possible to coordinate efforts at multiple levels, including public administrations and nonprofit organizations, to improve the diagnosis and treatment of retinoblastoma and to improve the outcome for these children.

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