Molecular Targeting of H/MDM-2 Oncoprotein in Human Colon Cancer Cells and Stem-like Colonic Epithelial-derived Progenitor Cells.

BACKGROUND/AIM: We have tested whether the anticancer peptide, PNC-27, that kills cancer cells but not normal cells by binding to cancer cell membrane HDM-2 forming pores, kills CD44+ colon cancer stem cells. MATERIALS AND METHODS: Flow cytometry determined the CD44 and HDM-2 expression on six-colon cancer cell lines and one normal cell line (CCD-18Co). MTT, LDH release, annexin V binding and caspase 3 assays were used to assess PNC-27-induced cell death. Bioluminescence imaging measured PNC-27 effects on in vivo tumor growth. RESULTS: High percentages of cells in all six tumor lines expressed CD44. PNC-27 co-localized with membrane HDM-2 only in the cancer cells and caused total cell death (tumor cell necrosis, high LDH release, negative annexin V and caspase 3). In vivo, PNC-27 caused necrosis of tumor nodules but not of normal tissue. CONCLUSION: PNC-27 selectively kills colon cancer stem cells by binding of this peptide to membrane H/MDM-2.

Gastric Cancer Peritoneal Carcinomatosis Risk Score.

BACKGROUND: Gastric cancer (GC) peritoneal carcinomatosis (PC) is associated with a poor prognosis. Although grade, histology, and stage are associated with PC, the cumulative risk of PC when multiple risk factors are present is unknown. This study aimed to develop a cumulative GCPC risk score based on individual demographic/tumor characteristics. METHODS: Patient-level data (2004-2014) from the California Cancer Registry were reviewed by creating a keyword search algorithm to identify patients with gastric PC. Multivariable logistic regression was used to assess demographic/tumor characteristics associated with PC in a randomly selected testing cohort. Scores were assigned to risk factors based on beta coefficients from the logistic regression result, and these scores were applied to the remainder of the subjects (validation cohort). The summed scores of each risk factor formed the total risk score. These were grouped, showing the percentages of patients with PC. RESULTS: The study identified 4285 patients with gastric adenocarcinoma (2757 males, 64.3%). The median age of the patients was 67 years (interquartile range [IQR], 20 years). Most of the patients were non-Hispanic white (n = 1748, 40.8%), with proximal (n = 1675, 39.1%) and poorly differentiated (n = 2908, 67.9%) tumors. The characteristics most highly associated with PC were T4 (odds ratio [OR], 3.12; 95% confidence interval [CI], 2.19-4.44), overlapping location (OR 2.27; 95% CI 1.52-3.39), age of 20-40 years (OR 3.42; 95% CI 2.24-5.21), and Hispanic ethnicity (OR 1.86; 95% CI 1.36-2.54). The demographic/tumor characteristics used in the risk score included age, race/ethnicity, T stage, histology, tumor grade, and location. Increasing GCPC score was associated with increasing percentage of patients with PC. CONCLUSION: Based on demographic/tumor characteristics in GC, it is possible to distinguish groups with varying odds for PC. Understanding the risk for PC based on the cumulative effect of high-risk features can help clinicians to customize surveillance strategies and can aid in early identification of PC.

Sexual and urinary outcomes in robotic rectal surgery: review of the literature and technical considerations.

Several studies have reported high rates of urogenital dysfunction after open and laparoscopic surgery for rectal cancer. Robotic surgery has several features that could facilitate identification and preservation of autonomic nerves. This manuscript aims to summarize the literature regarding urogenital function after robotic rectal cancer surgery and focus on technical aspects of nerve-sparing total mesorectal excision. Comprehensive searches were conducted through online databases. Selection criteria included: original articles assessing urinary and sexual function after robotic surgery of males and/or females with standardized questionnaires. A total of 16 articles were included in the review. Seven of the nine cohort studies evaluating male sexual function showed earlier recovery or better outcomes in patients operated with robotic techniques. Two studies did not find any statistically significant difference. Three out of four case series found no difference in sexual function scores measured preoperatively and after 1 year. Female sexual function was assessed in seven studies: two case series show no deterioration of at 1 year. Three comparative studies showed no difference between robotic and laparoscopic groups. Two randomized control trials showed different results in terms of male and female sexual functions with better preservation at 1 year in the robotic group in one and no difference in another. Urinary functions assessed in males and/or females in the 16 studies showed no statistically significant differences at long-term follow-up. At present, there is no evidence of superiority of robotic surgery for performing nerve-sparing rectal cancer surgery.

High-Risk Stage II Colon Cancer: Not All Risks Are Created Equal.

INTRODUCTION: Adjuvant chemotherapy is recommended in patients with stage II colon cancer with high-risk features (HRF). However, there is no quantification of the amount of risk conferred by each HRF or the overall survival (OS) benefit gained by chemotherapy based on the risk factor. OBJECTIVE: To assess survival benefits associated with adjuvant chemotherapy among stage II colon cancer patients having one or more HRF [T4 tumors, less than 12 lymph nodes examined (< 12LN), positive margins, high-grade tumor, perineural invasion (PNI), and lymphovascular invasion (LVI)]. METHODS: Patients diagnosed with stage II colon cancer between 2010 and 2013 were identified from California Cancer Registry. Propensity score weighted all-cause mortality hazard ratios (HR) were calculated for combinations of HRF. RESULTS: A total of 5160 stage II colon cancer patients were identified, of which 2398 had at least one HRF and 510 of 2398 (21%) received adjuvant chemotherapy. Compared with patients with a single HRF, presence of any 2 or ≥ 3 HRF showed increasingly poorer survival [HR 1.42, 95% confidence interval (CI) 1.16-1.73 and HR 2.50, 95% CI 1.96-3.20, respectively]. Chemotherapy was associated with improved overall survival only among patients with T4 as the single HRF (HR 0.51, 95% CI 0.34-0.78) or combinations involving T4 as T4/< 12 LN (HR 0.31, 95% CI 0.11-0.90), T4/high grade (HR 0.26, 95% CI 0.11-0.61), and T4/LVI (HR 0.16, 95% CI 0.04-0.61). CONCLUSIONS: Not all high-risk features have similar adverse effects on OS. T4 tumors and their combination with other HRF achieve the most survival benefit with adjuvant therapy. Type and number of high-risk features should be taken into consideration when recommending adjuvant chemotherapy in stage II colon cancer.

Emerging Role of MDM2 as Target for Anti-Cancer Therapy: A Review.

The mouse/murine protein, MDM2, and its human homolog, HDM2, are important negative regulators of the p53 tumor suppressor protein. In normal, untransformed cells, MDM2 levels are tightly regulated to control expression of p53 and apoptosis. Conversely, MDM2 expression appears inherently higher in multiple types of cancer cells, thereby supporting its role as a suppressor of p53 pro-apoptotic activity. MDM2 amplification ranges between two- and ten-fold as reported in brain, breast, lung, and soft tissue tumors. MDM2 regulates p53 by two mechanisms: acting as a physical blockade of the transcriptional activation domain and E3 ubiquitin ligase. In addition to its relationship with p53, MDM2 behaves as an independent oncogene. These inherent characteristics make MDM2 a promising target for developing anti-cancer therapies. Investigators are now exploring both p53- dependent and independent cancer cell death pathways by targeting MDM2. Disrupting MDM2-p53 interaction with resultant increase in p53 induces cancer cell cycle arrest and apoptosis. Targeting over-expressed MDM2 on cancer cell membranes disrupts membrane integrity by pore formation, causing membrane destabilization and rapid cancer cell-specific necrosis. In this review, evidence supporting the evolving role of MDM2 as an anti-cancer target and a molecular-based tumor biomarker will be discussed.

Palliative Surgery for Advanced Cancer: Identifying Evidence-Based Criteria for Patient Selection: Case Report and Review of Literature.

BACKGROUND: Criteria for selecting patients with advanced cancer for palliative surgery (PS) remains poorly defined. Decision making for PS requires realistic treatment goals with well-defined criteria. Here we discuss a 71-year-old Jehovah's Witness with advanced stage renal cell carcinoma (RCC) who presented with profound anemia due to intractable bleeding from gastric metastasis. After repeated attempts with endoscopic and angiographic management, she underwent surgical palliation. Through this case, we developed 10-item evidence-based criteria for selecting patients for PS. OBJECTIVE: The study objective was to provide a review of pertinent literature for PS and identify evidence-based criteria for patient selection. These criteria were relevant for selecting this patient with metastatic RCC and may prove beneficial for selecting advanced cancer patients for PS. METHODS: A MEDLINE search revealed 175 publications relevant to PS. Among these, 17 articles defining patient selection criteria (PSC) were reviewed. A frequency-based analysis of each criterion was performed. Another search returned 30 cases of RCC gastric metastases from 25 published reports. Outcome analysis was determined by the Kaplan-Meier actuarial method. RESULTS: Ten criteria were identified: symptom control, prognosis, preoperative performance status, quality of life (QoL), tumor burden amenable to palliation, procedure-related morbidity and mortality, feasibility of nonsurgical therapies, anticipated hospitalization, requirement for additional palliation, and cost. This patient met all inclusion criteria and underwent a successful gastrectomy. Median survival for patients with RCC gastric metastasis was 20 months. CONCLUSIONS: This report illustrates an example of implementation of evidence-based criteria for selecting advanced cancer patients for PS. Validation of these criteria is warranted.

Pancreatic mucinous cystic neoplasm in a transgender patient.

BACKGROUND: Cystic pancreatic lesions are increasingly more frequent detected clinical entities. Mucinous cystic neoplasm (MCN) is a hormone-related pancreatic tumor (HRTP) with a strong predominance in young and middle-aged females. CASE PRESENTATION: Here, we present the case of a 31-year-old surgically transgendered female-to-male patient with a history of alcoholic pancreatitis, on chronic testosterone therapy. He was found to have a pancreatic MCN and underwent distal pancreatectomy and splenectomy. CONCLUSION: To our knowledge, this is the first reported case of a transgender patient with a history of hormone replacement therapy (HRT) and pancreatic MCN. We consider possible mechanisms for the pathogenesis to explain this patient's neoplasm.

The anti-cancer peptide, PNC-27, induces tumor cell necrosis of a poorly differentiated non-solid tissue human leukemia cell line that depends on expression of HDM-2 in the plasma membrane of these cells.

GOALS: We have developed the anti-cancer peptide, PNC-27, which is a membrane-active peptide that binds to the HDM-2 protein expressed in the cancer cell membranes of solid tissue tumor cells and induces transmembrane pore formation in cancer, but not in normal cells, resulting in tumor cell necrosis that is independent of p53 activity in these cells. We now extend our study to non-solid tissue tumor cells, in this case, a primitive, possible stem cell human leukemia cell line (K562) that is also p53-homozygously deleted. Our purpose was twofold: to investigate if these cells likewise express HDM-2 in their plasma membranes and to determine if our anti-cancer peptide induces tumor cell necrosis in these non-solid tissue tumor cells in a manner that depends on the interaction between the peptide and membrane-bound HDM-2. PROCEDURES: The anti-cancer activity and mechanism of PNC-27, which carries a p53 aa12-26-leader sequence connected on its carboxyl terminal end to a trans-membrane-penetrating sequence or membrane residency peptide (MRP), was studied against p53-null K562 leukemia cells. Murine leukocytes were used as a non-cancer cell control. Necrosis was determined by measuring the lactate dehydrogenase (LDH) release and apoptosis was determined by the detection of Caspases 3 and 7. Membrane colocalization of PNC-27 with HDM-2 was analyzed microscopically using fluorescently labeled antibodies against HDM-2 and PNC-27 peptides. RESULTS: We found that K562 cells strongly express HDM-2 protein in their membranes and that PNC-27 co-localizes with this protein in the membranes of these cells. PNC-27, but not the negative control peptide PNC-29, is selectively cytotoxic to K562 cells, inducing nearly 100 percent cell killing with LDH release. In contrast, this peptide had no effect on the lymphocyte control cells. CONCLUSIONS: The results suggest that HDM-2 is expressed in the membranes of non-solid tissue tumor cells in addition to the membranes of solid tissue tumor cells. Since K-562 cells appear to be in the stem cell family, the results suggest that early developing tumor cells also express HDM-2 protein in their membranes. Since PNC-27 induces necrosis of K-562 leukemia cells and co-localizes with HDM-2 in the tumor cell membrane as an early event, we conclude that the association of PNC-27 with HDM-2 in the cancer cell membrane results in trans-membrane pore formation which results in cancer cell death, as previously discovered in a number of different solid tissue tumor cells. Since K562 cells lack p53 expression, these effects of PNC-27 on this leukemia cell line occur by a p53-independent pathway.

Retroperitoneal Castleman's disease: advocating a multidisciplinary approach for a rare clinical entity.

BACKGROUND: Castleman's disease is a rare and poorly understood disease entity that may resemble more common conditions and represents a clinical challenge to the treating surgeon. CASE PRESENTATION: In this report, we describe a case of a 61-year-old Caucasian woman with a symptomatic retroperitoneal mass. The specimen obtained from her resection contained a protuberant encapsulated mass, exhibiting microscopic features consistent with localized, unicentric Castleman's disease. These characteristics included architectural features and immunohistochemical findings consistent with the hyaline vascular variant of Castleman's disease. CONCLUSION: We report a very rare case of a retroperitoneal hyaline vascular type of Castleman's disease. We discuss the diagnostic dilemma Castleman's disease may present to the surgeon, with an emphasis on multidisciplinary management of these patients. We also review current data on pathogenesis, treatment and outcomes.

Maintaining a Sufficient and Quality Physician Workforce: The Role of For-profit Medical Schools.

Currently, in the United States there is a significant physician workforce shortage. This problem is likely to persist as there is no quick solution. The nature of this shortage is complex and involves factors such as an absolute physician shortage, as well as physician shortages in primary care and certain specialty care areas. In addition, there is a misdistribution of physicians to medically underserved areas and populations. The medical education system trains medical school graduates that eventually feed the physician workforce. However, several factors are in place which ultimately limits the effectiveness of this system in providing an appropriate workforce to meet the population demands. For-profit medical schools have been in existence in and around the continental US for many years and some authors have suggested that they may be a major contributor to the physician workforce shortage. There is currently one for-profit medical school in the US, however the majority exist in the Caribbean. The enrollment in and number of these schools have grown to partially meet the ever-growing demand for an increase in medical school graduates and they continue to provide a large number of graduates who return to the US for postgraduate medical training and, ultimately, increase the physician workforce. The question is whether this source will benefit the workforce quality and quantity needs of our growing and aging population.