Global Disparities in Breast Cancer Genetics Testing, Counselling and Management.

Hereditary breast cancers, mainly due to BRCA1 and BRCA2 mutations, account for only 5-10% of this disease. The threshold for genetic testing is a 10% likelihood of detecting a mutation, as determined by validated models such as BOADICEA and Manchester Scoring System. A 90-95% reduction in breast cancer risk can be achieved with bilateral risk-reducing mastectomy in unaffected BRCA mutation carriers. In patients with BRCA-associated breast cancer, there is a 40% risk of contralateral breast cancer and hence risk-reducing contralateral mastectomy is recommended, which can be performed simultaneously with surgery for unilateral breast cancer. Other options for risk management include surveillance by mammogram and breast magnetic resonance imaging, and chemoprevention with hormonal agents. With the advent of next-generation sequencing and development of multigene panel testing, the cost and time taken for genetic testing have reduced, making it possible for treatment-focused genetic testing. There are also drugs such as the PARP inhibitors that specifically target the BRCA mutation. Risk management multidisciplinary clinics are designed to quantify risk, and offer advice on preventative strategies. However, such services are only possible in high-income settings. In low-resource settings, the prohibitive cost of testing and the lack of genetic counsellors are major barriers to setting up a breast cancer genetics service. Family history is often not well documented because of the stigma associated with cancer. Breast cancer genetics services remain an unmet need in low- and middle-income countries, where the priority is to optimise access to quality treatment.

Recommendations on breast cancer screening and prevention in the context of implementing risk stratification: impending changes to current policies.

In recent years, risk stratification has sparked interest as an innovative approach to disease screening and prevention. The approach effectively personalizes individual risk, opening the way to screening and prevention interventions that are adapted to subpopulations. The international perspective project, which is developing risk stratification for breast cancer, aims to support the integration of its screening approach into clinical practice through comprehensive tool-building. Policies and guidelines for risk stratification-unlike those for population screening programs, which are currently well regulated-are still under development. Indeed, the development of guidelines for risk stratification reflects the translational aspects of perspective. Here, we describe the risk stratification process that was devised in the context of perspective, and we then explain the consensus-based method used to develop recommendations for breast cancer screening and prevention in a risk-stratification approach. Lastly, we discuss how the recommendations might affect current screening policies.

Concurrent chemoradiotherapy for locally advanced breast cancer-time for a new paradigm?

BACKGROUND: In cases of locally advanced breast cancer (labc), preoperative ("neoadjuvant") therapy was traditionally reserved to render the patient operable. More recently, neoadjuvant therapy, particularly chemotherapy, is being used in patients with operable disease to increase the opportunity for breast conservation. Despite the increasing use of preoperative chemotherapy, rates of pathologic complete response, a surrogate marker for disease-free survival, remain modest in patients with locally advanced disease and particularly so when the tumour is estrogen or progesterone receptor-positive and her2-negative. A new paradigm for labc patients is needed. In other solid tumours (for example, rectal, esophageal, and lung cancers), concurrent chemoradiotherapy (ccrt) is routinely used in neoadjuvant and adjuvant treatment protocols alike. RESULTS: The literature suggests that ccrt in labc patients with inoperable disease is associated with response rates higher than would be anticipated with systemic therapy alone. CONCLUSIONS: Ongoing trials in this field are eagerly awaited to determine if ccrt should become the new paradigm.

Phase II trial of short-course radiotherapy followed by delayed surgery for locoregionally advanced rectal cancer.

AIM: A prospective phase II study to investigate the feasibility and the rate of complete pathological response (ypT0) after short-course radiotherapy (SCRT) followed by surgery at 8 weeks. METHOD: Operable patients with localized rectal cancer staged T3-4N0/+ or T2N+ were eligible and received 25 Gy (in one-third of patients, the gross tumor volume received a simultaneous integrated boost up to a total of 30 Gy) in five consecutive fractions to the posterior pelvis followed by surgery 8 weeks later. Pathological response and surgical toxicity were assessed in all patients. RESULTS: Fifty-two patients (median age 68 years) completed the study. The median distance of the tumour from the anal verge was 6.5 cm. The median interval to surgery was 52 days. Three-quarters of patients underwent a low anterior resection. All underwent complete surgical resection and 100% had pathological negative margins. Ten per cent had stage ypT0 after radiotherapy. The median length of hospital stay was 8 days. Toxicity was comparable with the rates reported in the literature. CONCLUSION: In this study, SCRT followed by delayed surgery was feasible and had acceptable toxicity. All patients underwent complete surgical resection and 100% had negative pathological margins. The rate of ypT0 was 10%.

Systematic review and meta-analysis of the effect of North American working hours restrictions on mortality and morbidity in surgical patients.

BACKGROUND: Short duty hours, imposed by the Accreditation Council of Graduate Medical Education (ACGME) regulations, have been claimed to be associated with loss of continuity of care among surgical patients, leading to a potentially increased risk of adverse surgical outcomes. This systematic review and meta-analysis assessed the strength of associations between duty hour restrictions and morbidity and mortality of various surgical procedures. METHODS: MEDLINE, Embase, BIOSIS Previews(®), the Education Resources Information Center and the Cochrane Central Register of Controlled Trials (January 2000 to September 2009) were searched, and reports screened to identify comparative studies of mortality and morbidity before and after the introduction of ACGME regulation periods. Random-effects (RE) and quality-effects (QE) meta-analyses were performed to determine the risk of morbidity or death associated with long duty hours compared with shorter duty hours. Results are presented as odds ratio (OR) with 95 per cent confidence interval. RESULTS: A total of 19 data sets (10 articles), including 730,648 subjects in the mortality studies and 64,346 in the morbidity studies, were analysed. Long duty hours were associated with a non-significantly increased risk of death compared with shorter duty hours (OR 1·28, 0·94 to 1·73). There was no difference in morbidity between the two groups (OR 1·03, 0·67 to 1·57). Mortality associations were generally stronger for general surgery, more recent studies and higher-quality studies. Heterogeneity was evident among the studies included. CONCLUSION: The reduction in working hours has not affected patient care negatively in terms of demonstrable differences in morbidity and mortality. However, it cannot be distinguished whether this effect is actually due to a non-detrimental effect of the reduction in working hours or whether any such detriment is offset by continually improving patient care and increased surgical supervision.

Validation study of the s classification for melanoma patients with positive sentinel nodes: the Montreal experience.

BACKGROUND: Standard of care is to perform a complete lymph node dissection (CLND) in melanoma patients with positive sentinel lymph nodes (SLNs). However, less than 20% will have metastases in non-SLNs. The S classification was described to predict the non-SLN status, hoping to identify a subset of patients who can be spared the CLND. We tried to validate the feasibility and usefulness of this classification. MATERIALS AND METHODS: We performed a retrospective chart review. All melanoma cases between 1996 and 2006 were included, and 359 patients with SLN biopsies were identified. All pathology slides were reviewed with an emphasis on the S classification. RESULTS: There were 365 SLN biopsies performed. A total of 82 patients (22.8%) had positive SLNs, while 277 patients (77.2%) had negative SLNs. There were 22 patients classified as SI, 18 as SII, 37 as SIII, and 5 were unclassified. On CLND, only 10 patients (12.2%) had positive non-SLNs. None of these were classified as SI while 2 patients (11%) were classified as SII and 8 (22%) as SIII. The S category was found to be a predictor of non-SLN status, and this reached statistical significance (P = 0.044). On univariate analysis, only an increasing Breslow depth and ulceration were predictive of a non-SI status. CONCLUSION: Our results suggest that the S classification is easily feasible and predicts the status of non-SLNs. No patient with SI status was found to have additional non-SLN positive nodes. A larger-scale, prospective trial should be done to confirm these results and possibly spare patients the morbidity of CLND with a positive SLN.

Rapid induction of cytokine and E-selectin expression in the liver in response to metastatic tumor cells.

The cytokine-inducible endothelial cell adhesion receptor E-selectin has been implicated in cancer metastasis. Previously, we reported that experimental liver metastasis of Lewis lung carcinoma subline H-59 cells could be abrogated in animals treated with an anti-E-selectin antibody. To gain further insight into the functional relevance of E-selectin expression to liver colonization, we investigated here the time course of cytokine and hepatic E-selectin expression after the intrasplenic/portal inoculation of H-59 cells by using a combination of reverse transcription-PCR, Northern blot analysis, immunohistochemistry, and in situ hybridization. In parallel, we analyzed cytokine induction in response to the injection of Lewis lung carcinoma subline M-27 and murine melanoma B16-F1 cells, which do not spontaneously metastasize to the liver. In livers derived from normal or saline-injected mice, only minimal basal levels of TNF-alpha and IL-1 mRNA were detectable by RT-PCR. Rapid cytokine mRNA induction was noted within 30-60 min of H-59 injection, reaching maximal levels at 4-6 h. This was followed by the appearance of E-selectin mRNA, which was detectable at 2 h after injection and reached maximal levels at 6-8 h, declining to basal levels by 24 h. In situ hybridization analysis and immunohistochemistry localized E-selectin mRNA and protein, respectively, to the sinusoidal endothelium. M-27 cells failed to induce cytokine or E-selectin expression, whereas B-16 cells elicited a delayed and more short-lived response. The results demonstrate that upon entry into the hepatic circulation, tumor cells can rapidly trigger a molecular cascade leading to the induction of E-selectin expression on the sinusoidal endothelium and suggest that E-selectin induction may contribute to the liver-colonizing potential of tumor cells.

Human and murine Kupffer cell function may be altered by both intrahepatic and intrasplenic tumor deposits.

The liver is the most common site of hematogenous metastases from colorectal carcinoma. Kupffer cells (KC), which line the hepatic sinusoids, may form the first line of defense against circulating tumor cells. The purpose of this study was to determine the effect of hepatic metastases and intra-abdominal tumor growth on KC binding of human colorectal carcinoma (HCRC) cells. MIP-101, a poorly metastatic cell line, and CX-1, a highly metastatic cell line, were injected intrasplenically into nude mice and KC were isolated by collagenase perfusion at varying intervals after injection. Conditioned media were collected from MIP-101, CCL 188 and CX-1 to determine their in vitro effect on KC function. KC from MIP-101 injected mice (14% liver metastases, 100% splenic tumors) bound a significantly greater number of MIP-101 and clone A cells than CX-1 cells in vitro. KC isolated from mice 5 weeks after CX-1 injection (100% liver metastases) also showed increased binding of MIP-101 and clone A cells compared to CX-1 cells. Similar results were obtained when tumor cell binding to normal human liver KC was compared to binding to KC from human livers from patients with hepatic metastasis from colorectal cancer. In contrast KC obtained from mice 3 weeks after CX-1 injection (44% liver metastases) showed significantly decreased binding of MIP-101 and clone A cells. The conditioned medium from CX-1 cells significantly decreased the in vitro binding of both MIP-101 and CX-1 by KC. These results indicate that the ability of KC to bind HCRC cells (which precedes phagocytosis and tumor cell killing) is a dynamic function and affected by concomitant tumor growth. HCRC cells may alter KC function via the production of specific tumor-derived soluble factors. In order to devise new and more effective therapeutic options in the treatment of liver metastases the nature of this tumor cell-KC interaction must be better understood.

Desialylation of metastatic human colorectal carcinoma cells facilitates binding to Kupffer cells.

Cell surface hypersialylation of human colorectal carcinoma (HCRC) cells correlates with increased metastatic potential after intrasplenic injection, while desialylation with various agents has been shown to inhibit hepatic metastases. In this study we examined the effects of desialylation of HCRC cell lines with a novel intracellular inhibitor of the CMP-sialic acid transport protein (KI-8110). HCRC cells, which are poorly differentiated and poorly metastatic in nude mice (Clone A and MIP-101) were compared to well-differentiated, highly metastatic cells (CX-1 and CCL-235). KI-8110 treatment has previously been shown to reduce sialic acid levels in each of these cell lines and to reduce hepatic metastases in CX-1 and CCL-235 cell lines. This study attempts to identify a mechanism by which desialylation inhibits hepatic metastases. After KI-8110 treatment, in vitro adhesion assays were performed with each cell line to examine binding to Kupffer cells and the extracellular matrix protein fibronectin. Binding of Clone A, CX-1, and CCL-235 to Kupffer cells was significantly increased after KI-8110 treatment. Desialylation had no significant effect on binding of HCRC cell lines to fibronectin. While the metastatic cascade involves many complex interactions, the cytotoxic effects of Kupffer cells in the hepatic sinusoid are known to be an important mechanism of host defense against tumor cells. Cell surface sialic acids may well mask Kupffer cell binding to HCRC cells, preventing their cytotoxic effects and enhancing the metastatic potential of circulating tumor cells.

Preoperative infusional chemoradiation therapy for stage T3 rectal cancer.

PURPOSE: To evaluate preoperative infusional chemoradiation for patients with operable rectal cancer. METHODS AND MATERIALS: Preoperative chemoradiation therapy using infusional 5-fluorouracil (5-FU), (300 mg/m2/day) together with daily irradiation (45 Gy/25 fractions/5 weeks) was administered to 77 patients with clinically Stage T3 rectal cancer. Endoscopic ultrasound confirmed the digital rectal exam in 63 patients. Surgery was performed approximately 6 weeks after the completion of chemoradiation therapy and included 25 abdominoperineal resections and 52 anal-sphincter-preserving procedures. RESULTS: Posttreatment tumor stages were T1-2, N0 in 35%, T3 N0 in 25%, and T1-3, N1 in 11%; 29% had no evidence of tumor. Local tumor control after chemoradiation was seen in 96% (74 out of 77); 2 patients had recurrent disease at the anastomosis site and were treated successfully with abdominoperineal resection. Overall, pelvic control was obtained in 99% (76 out of 77). The survival after chemoradiation was higher in patients without node involvement than in those having node involvement (p = n.s.). More patients with pathologic complete responses or only microscopic foci survived than did patients who had gross residual tumor (p = 0.07). The actuarial survival rate was 83% at 3 years; the median follow-up was 27 months, with a range of 3 to 68 months. Acute, perioperative, and late complications were not more numerous or more severe with chemoradiation therapy than with traditional radiation therapy (XRT) alone. CONCLUSIONS: Excellent treatment response allowed two-thirds of the patients to have an anal-sphincter-sparing procedure. Gross residual disease in the resected specimen indicates a poor prognosis, and therapies specifically targeting these patients may improve survival further.

Kupffer cell/tumor cell interactions and hepatic metastasis in colorectal cancer.

The degree of interaction with Kupffer cells of two moderately well differentiated cell lines, CX-1 and CCl-188 of high metastatic potential (61%) were compared to two poorly differentiated cell lines, MIP-101 and Clone A of low metastatic potential (6%) in the intrasplenic injection model for liver metastasis. MIP-101 and Clone A bound significantly better to mouse Kupffer cells in vitro than either CX-1 or CCL-188. We also identified specific cell surface proteins mediating attachment of colorectal carcinoma cells to murine Kupffer cells. Kupffer cells were radiolabelled and their surface proteins incubated with MIP-101 and CX-1. Two radiolabelled proteins from murine Kupffer cells of 14 and 34 kDa were identified consistently binding to the tumor cells. Binding of both proteins was inhibited by asialofetuin but not by fetuin. This suggests that the major binding proteins between Kupffer cells and colorectal cancer cells are galactose binding lectins.

Effect of membrane free fatty acid alterations on the adhesion of human colorectal carcinoma cells to liver macrophages and extracellular matrix proteins.

Epidemiologic studies have linked diets high in animal fat with colon carcinogenesis. A number of animal tumor models have shown that diets rich in omega-3 fatty acids inhibit colon carcinogenesis while diets rich in omega-6 fatty acids promote tumor growth. This study examines whether modification of the membrane fatty acid composition of both moderately (CX-1) and poorly differentiated (MIP-101 and Clone A) human colorectal carcinoma cells alters their interaction with Kupffer cells and extracellular matrix proteins (collagen type IV, fibronectin and laminin). The cells were treated with 15-16 micrograms/ml of docosahexanoic acid (22:6, omega 3) or linoleic acid (18:2,omega 6). Gas chromatography showed significant alterations in the membrane fatty acid composition of the human colorectal cancer cell lines. Binding assays were performed by measuring adherence of 51Cr-labelled tumor cells to Kupffer cell monolayers or to immobilized proteins. Omega-3 treatment significantly decreased the Kupffer cell binding of only the CX-1 line while omega-6 treatment decreased binding of all three cell lines. In contrast both omega-3 and omega-6 treatment of MIP-101 cells decreased binding to the extracellular matrix proteins with the omega-6 effect being more pronounced. These results indicate that the binding characteristics of the colon cancer cells to both Kupffer cells and extracellular matrix proteins may be determined in part by the membrane fatty acid composition. Decreased adherence to extracellular matrix proteins may lead to increased cell motility and invasiveness. Since Kupffer cell binding precedes tumor cell phagocytosis and killing, decreased binding may improve tumor cell survival.

Assessment of cardiac function in patients who were morbidly obese.

Cardiac function of 30 patients who were morbidly obese was studied before bariatric surgery. Twelve patients were studied 13 +/- 4 months after surgery. These patients had a mean age of 37.1 +/- 2.9 years and a body mass index of 50.0 +/- 1.4 kg/m2. Cardiac function was measured by echocardiography, radionuclide angiography scanning, and right heart catheterization. To determine the degree of cardiac dysfunction, the patients were studied with exercise and intravenous fluid challenges. Ultrasonography produced evidence of myocardial thickening with an increased interventricular septum in eight patients (32%) and increased left ventricular mass in 17 patients (53%). The radionuclide scan suggested that morbid obesity was associated with a significantly (p less than 0.05) increased end-diastolic volume and decreased left ventricular ejection fraction as compared with patients who were of normal weight. With exercise the patient who was of normal weight had an increase in the end-diastolic volume, stroke volume, and heart rate, but the patient who was morbidly obese only increased heart rate to produce the necessary increase in cardiac output. Right heart catheterization indicated that the relationship of the pulmonary wedge pressure and the left ventricular stroke work index was abnormal in 14 of 29 patients (48.3%) and depressed in six of 29 patients (20.7%) with exercise. One liter of fluid caused an abnormal relationship of the pulmonary wedge pressure and the left ventricular stroke work index in 12 of 30 patients (40%) and a depressed response in 10 of 30 patients (33.3%). Cardiac studies were repeated in 12 patients after a 54.8 +/- 1.9 kg weight loss. Echocardiography indicated a decrease in dilatation (27.3% to 9.1%) and a significant (p less than 0.05) decrease in hypertrophy (45.5% to 0%). After the weight loss, radionuclide and right heart catheterization studies indicated improved cardiac function with reduced filling pressures and increased left ventricular work during fluid and exercise challenges. These results support the presence of obesity-related cardiomyopathy with ventricular dysfunction, which appears to be caused by a noncompliant ventricle. Significant weight loss achieved with gastroplasty results in increased ventricular compliance and improved cardiac function.

Pelvic exenteration for locally advanced rectal carcinoma: factors predicting improved survival.

BACKGROUND: The purpose of this retrospective review was to determine whether a number of clinicopathologic factors (age, gender, type of exenteration, tumor extent, adjuvant therapy, tumor DNA ploidy, and S-phase fraction) that could be determined before operation were useful in predicting survival in patients undergoing pelvic exenteration for rectal cancer. METHODS: Between 1983 and 1992, 40 patients (15 male and 25 female) at our institution underwent pelvic exenteration for rectal adenocarcinoma in which tumor-free pathologic margins were obtained. Twenty-nine patients presented with primary tumors; 11 had recurrent disease. A total exenteration was performed in 20 patients, posterior exenteration in 18 patients, and an anterior exenteration in 2 patients. RESULTS: By multivariate (Cox proportional hazards regression) analysis, age, preoperative chemoradiation therapy, and an S phase of 10% or greater were found to be significant predictors of survival. Age older than 55 years was associated with a relative risk for cancer-related death (RR) of 0.13 (p = 0.02), and chemoradiation had an RR of 0.05 (p = 0.01), indicating their beneficial effect. An S-phase fraction of 10% or greater had an RR of 16.97 (p = 0.03), indicating a poor survival. The clinicopathologic factors listed above were used to derive a prognostic index (PI). A PI of less than 1.37 was associated with a 5-year survival rate of 65% (low risk), whereas patients with a PI of 1.37 or greater had a 5-year survival rate of 20% (high risk) (p = 0.005). CONCLUSIONS: These results indicate that adjuvant chemoradiation may significantly improve survival in patients who require pelvic exenteration for resection of locally advanced rectal carcinoma. An S-phase fraction of 10% or greater is also predictive of a poor outcome. Use of these factors allowed the generation of a PI that identifies high- and low-risk patients. Consideration of the ability to deliver chemoradiation and the determinates of the tumor S-phase fraction in patients requiring pelvic exenteration for rectal cancer may be helpful in predicting outcome and planning therapy.

Merkel cell carcinoma: important aspects of diagnosis and management.

Merkel cell carcinoma (MCC) is a highly aggressive primary neuroendocrine tumor. It is suggested in the literature that postoperative radiotherapy may decrease local recurrence and improve overall survival. The purpose of this retrospective review was to determine our experience and review the literature on this aggressive malignancy. Charts of ten patients with MCC seen between 1985 and 1997 were reviewed to obtain clinicopathological data. Eight patients were male with a mean age of 72 years (range 49-90). The head and neck was the most common site, affecting 50 per cent of patients. All patients had primary excisions with documented negative margins. Pathological size ranged from 10 to 40 mm. Initial pathological diagnosis was lymphoma in three cases requiring immunohistochemistry for cytokeratin and neuron-specific enolase for definitive diagnosis. Lymphatic invasion was noted in three patients but only one of these patients had clinical lymph node involvement. The mean follow-up was 54 months (range 6-114) with an 80 per cent one-year survival and 30 per cent 2-year survival. Postoperative radiotherapy was administered to five patients. Of these three died with evidence of both local and distant recurrence. This small retrospective review highlights important points in the management of MCC including pathological diagnosis and benefits of adjuvant radiation therapy.

Randomized clinical trial of the anabolic effect of hypocaloric parenteral nutrition after abdominal surgery.

BACKGROUND: The observed failure of hypocaloric nutrition to establish an anabolic state after surgery may reflect inadequate control for the type and quality of analgesia in the studies performed. This study was designed to test the hypothesis that hypocaloric nutrition induces anabolism in patients who receive effective segmental pain relief using perioperative epidural analgesia. METHODS: Sixteen patients who underwent colorectal surgery and received epidural analgesia were randomly assigned to receive intravenous glucose either without (glucose only) or with amino acids (nutrition). Feeding was administered over 48 h from surgical skin incision until the second day after operation. Glucose provided 50 per cent of the patient's resting energy expenditure (REE). Amino acids were infused at rates that provided 20 per cent of REE. Leucine rate of appearance (Ra), leucine oxidation and non-oxidative leucine disposal (NOLD) were assessed by measuring L-[1-13C]leucine kinetics. A positive leucine balance, that is the difference between NOLD and leucine Ra, indicated anabolism. RESULTS: After surgery, leucine Ra in the nutrition group was lower than that in the glucose only group (mean(s.d.) 88(25) versus 131(22) micromol per kg per h). The leucine balance remained negative in the glucose only group, whereas it became positive in the nutrition group (mean(s.d.) -24(3) versus 38(12) micromol per kg per h; P < 0.001). CONCLUSION: Patients who receive hypocaloric parenteral nutrition can be rendered anabolic after colorectal surgery in the presence of epidural analgesia.

Morphometry of the distribution of hydrostatic pulmonary oedema in dogs.

Light microscopic morphometry was utilized to examine the distribution of fluid in the interstitium around arteries, veins and within bronchovascular bundles in hydrostatic oedema, comparing it with previous control and permeability oedema experiments. Pulmonary artery wedge pressure was raised with fluid overload and an aortic balloon in five anaesthetized dogs to produce oedema (wet weight to dry weight ratios of 11.66 +/- 0.84). Lung lobes were fixed by freeze-substitution at 20 mmHg airway pressure. Photomicrographs of arteries, veins and bronchovascular bundles were taken, and areas were digitized to obtain the following: for arteries and veins, an oedema ratio=perivascular oedema cuff area/vessel area; for bronchovascular bundles, T=total bundle area, A1=interstitial area around airways, B=airway (respiratory bronchiole, bronchiole, or bronchus) area, A2=periarterial interstitium, V=artery area. From these, oedema ratios were calculated as A1/B and A2/V. We found that the oedema ratios were greater (P less than 0.01) for arteries (1.18, n=675) than veins (0.56, n=263), and were greater for the larger vessels; A1 rose significantly (P less than 0.01) only in bronchovascular bundles with bronchioles and bronchi, not in those with respiratory bronchioles; A2 increased from three- to 25-fold (P less than 0.01) in all bundles; A1/B only increased in bundles with bronchi while A2/V increased two- to six-fold in all bundles with oedema compared with controls. We conclude that these preferential patterns of distribution resemble those reported in permeability oedema, and may shed light on mechanisms of accumulation, and on the physiological effects of oedema on airways and vessels of the lung.

Fas/APO-1 expression and function on malignant cells of hematologic and nonhematologic origin.

Fas/APO-1 is a cell-surface protein capable of inducing apoptosis in a variety of cell types upon specific antibody engagement. Antibodies against Fas/APO-1 have been used successfully for the treatment of several lymphoid malignancies in mice. Before apoptosis triggered by anti-Fas can be fully exploited as a clinical therapy, Fas/APO-1 distribution, function, and regulation must be further studied. In this study, we analyzed freshly isolated B-cell and T-cell lymphomas as well as nonhematological tumor cell lines for Fas/APO-1 expression and sensitivity to the growth-inhibitory effects of anti-Fas. Constitutive Fas/APO-1 was expressed at very low levels on only one of eight B-cell lymphomas analyzed. Expression was markedly up-regulated, however, by culture with high-molecular-weight B-cell growth factor (HMW-BCGF). Fas/APO-1 was constitutively expressed on one of two T-cell lymphomas examined at levels comparable to those of activated normal lymphocytes. However, neither the B-cell nor T-cell lymphomas positive for Fas/APO-1 expression were growth inhibited by anti-Fas. Furthermore, in the case of one HMW-BCGF-activated B-cell lymphoma, a significant growth enhancement was observed upon anti-Fas treatment. Nonhematologic tumor cell lines showed a similar spectrum of biologic responses to anti-Fas, being growth inhibited, growth stimulated or unaffected by antibody treatment. In summary, these studies suggest that engagement of Fas/APO-1 may trigger a diverse spectrum of biologic effects not unlike other members of the nerve growth factor receptor/tumor necrosis factor receptor superfamily.

Omega-6 fatty acids can inhibit Fas-mediated apoptosis in a human colorectal carcinoma cell line: a potential mechanism for escape from immune surveillance.

The Fas/Fas ligand pathway may play an important role in the pathogenesis of colorectal carcinoma by allowing tumor cells to evade host immune defenses. Since dietary fats, in particular omega-6 fatty acids, facilitate tumor development their influence on the Fas/Fas ligand pathway needs to be elucidated. The purpose of this study was to determine the effect of membrane free fatty acid (FFA) alterations on Fas expression and sensitivity. Two human colorectal carcinoma cell lines (CX-1 and CCL-188) were grown in cell culture media supplemented with omega-3 (docosahexanoic acid) and omega-6 (linoleic acid) fatty acids. Membrane alterations were confirmed by gas chromatography (GC). Cell surface Fas expression was determined with flow cytometry using an anti-Fas monoclonal antibody. Sensitivity to Fas mediated apoptosis was measured by now cytometric measurement of fragmented DNA stained with propidium iodide. Appropriate changes in the membrane FFA composition were found by GC. Cell surface Fas expression was unaffected in either cell line. Omega-3 fatty acids did not alter Fas sensitivity for either cell line compared to control (CX-1: 59.7%, +/- 5.4 vs 51.4% +/- 7.1 for control, CCL-188: 54.3% +/- 8.6 vs 51.2% +/- 4.8 for control). Omega-6 fatty acids produced a significant decrease in Fas-mediated apoptosis (CX-1: 34.2% +/- 4.8 and CCL-188: 22% +/- 6.0, p < 0.05 vs control). These data indicate that although membrane FFA alterations did not affect Fas expression, omega-6 fatty acids significantly decreased Fas-mediated apoptosis. This inhibitory effect may protect colorectal carcinoma cells from lymphocyte Fas-mediated cell death.