High- and intermediate-risk susceptibility variants in melanoma families from the Mediterranean area: A multicentre cohort from the MelaNostrum Consortium.

BACKGROUND: Most of large epidemiological studies on melanoma susceptibility have been conducted on fair skinned individuals (US, Australia and Northern Europe), while Southern European populations, characterized by high UV exposure and dark-skinned individuals, are underrepresented. OBJECTIVES: We report a comprehensive pooled analysis of established high- and intermediate-penetrance genetic variants and clinical characteristics of Mediterranean melanoma families from the MelaNostrum Consortium. METHODS: Pooled epidemiological, clinical and genetic (CDKN2A, CDK4, ACD, BAP1, POT1, TERT, and TERF2IP and MC1R genes) retrospective data of melanoma families, collected within the MelaNostrum Consortium in Greece, Italy and Spain, were analysed. Univariate methods and multivariate logistic regression models were used to evaluate the association of variants with characteristics of families and of affected and unaffected family members. Subgroup analysis was performed for each country. RESULTS: We included 839 families (1365 affected members and 2123 unaffected individuals). Pathogenic/likely pathogenic CDKN2A variants were identified in 13.8% of families. The strongest predictors of melanoma were ≥2 multiple primary melanoma cases (OR 8.1; 95% CI 3.3-19.7), >3 affected members (OR 2.6; 95% CI 1.3-5.2) and occurrence of pancreatic cancer (OR 4.8; 95% CI 2.4-9.4) in the family (AUC 0.76, 95% CI 0.71-0.82). We observed low frequency variants in POT1 (3.8%), TERF2IP (2.5%), ACD (0.8%) and BAP1 (0.3%). MC1R common variants (≥2 variants and ≥2 RHC variants) were associated with melanoma risk (OR 1.4; 95% CI 1.0-2.0 and OR 4.3; 95% CI 1.2-14.6, respectively). CONCLUSIONS: Variants in known high-penetrance genes explain nearly 20% of melanoma familial aggregation in Mediterranean areas. CDKN2A melanoma predictors were identified with potential clinical relevance for cancer risk assessment.

Reliability and accuracy of the brachial plexus neurodynamic test.

STUDY DESIGN: Observational study. INTRODUCTION: The brachial plexus neurodynamic test (BPNT), based on previous neurodynamic tests, is considered a clinically meaningful tool to objectively assess brachial plexus extensibility. This novel test's psychometric properties have yet to be determined. PURPOSE OF THE STUDY: The primary study aim was to assess the inter- and intrarater reliability and accuracy of the BPNT, which biases the median nerve and brachial plexus, among clinicians of various professional experience levels and geographic US regions. The secondary study aim was to determine if professional experience or geographic region affects the accuracy levels of this test. METHODS: In phase 1, inter-rater reliability and accuracy was determined. About 307 participants attending neural mobilization conferences and courses were instructed in the BPNT and asked to score 7 different videos of 14 possible test levels. In phase 2, intrarater reliability was determined via scoring the same test videos twice. RESULTS: High inter-rater intraclass correlation coefficient (range, 0.98-0.99) and accuracy (range, 0.88-0.94) levels were determined for all clinical experience levels and geographic regions. Intrarater intraclass correlation coefficient values were high (range, 0.96-1.0) among all participants. One-way analysis of variance indicated no significant differences on test accuracy based on professional clinical experience (F = 0.104; P = .958) and geographic region (F = 0.416; P = .416) among all 307 participants. DISCUSSION: Excellent inter- and intrarater reliability and accuracy levels may allow clinicians to correctly identify BPNT positions regardless of their professional experience or geographic location. CONCLUSION: The BPNT can reliably and accurately quantify outcomes in neural mobility scoring.

Mammalian (cytosine-5) methyltransferases cause genomic DNA methylation and lethality in Drosophila.

CpG methylation is essential for mouse development as well as gene regulation and genome stability. Many features of mammalian DNA methylation are consistent with the action of a de novo methyltransferase that establishes methylation patterns during early development and the post-replicative maintenance of these patterns by a maintenance methyltransferase. The mouse methyltransferase Dnmt1 (encoded by Dnmt) shows a preference for hemimethylated substrates in vitro, making the enzyme a candidate for a maintenance methyltransferase. Dnmt1 also has de novo methylation activity in vitro, but the significance of this finding is unclear, because mouse embryonic stem (ES) cells contain a de novo methylating activity unrelated to Dnmt1 (ref. 10). Recently, the Dnmt3 family of methyltransferases has been identified and shown in vitro to catalyse de novo methylation. To analyse the function of these enzymes, we expressed Dnmt and Dnmt3a in transgenic Drosophila melanogaster. The absence of endogenous methylation in Drosophila facilitates detection of experimentally induced methylation changes. In this system, Dnmt3a functioned as a de novo methyltransferase, whereas Dnmt1 had no detectable de novo methylation activity. When co-expressed, Dnmt1 and Dnmt3a cooperated to establish and maintain methylation patterns. Genomic DNA methylation impaired the viability of transgenic flies, suggesting that cytosine methylation has functional consequences for Drosophila development.

Comparisons of beliefs in mental health stigma in communities and those who police them.

The police response towards people with mental illness (PwMI) is coming under increasingly intense scrutiny. Numerous jurisdictions have experienced incidents where the police have used force against persons who were exhibiting symptoms of severe mental illness. PwMI are subject to long-held stereotypes and stigma, and recent research indicates these negative attitudes remain, even with training and awareness campaigns. Available literature provides research on citizen and police perceptions of PwMI separately, but no recent studies have compared perceptions of police officers to those held by the members of the communities they patrol. The current study involves a comparison of residents in five southern New Jersey counties and police officers working in these same counties. Both sets of participants responded to a series of statements about perceptions of PwMI. Police were more likely to report supporting stigmatizing views of PwMI than were community members. Negative community response and rejection of police tactics may be rooted partly in differing expectations of treatment towards PwMI in crisis.

Officer Trust Towards Community Members and Critical Incidents: a Comparison of Factors.

Current scholarship suggests attention should be focused on differences in specific job-related conditions to understand help-seeking behavior among police officers. This project examines how officers' feelings of department satisfaction and on-the-job emotions may be associated with trust in members of the community they police. Specifically, officers were asked to report trust levels both in a general sense and in the context of a potential officer-involved shooting (OIS) incident. Print and electronic surveys were completed by 169 police officers across 9 agencies located in 5 New Jersey counties between September 2019 and March 2020. Survey questions covered frequency of on-the-job emotions, satisfaction with department administration, and knowledge of local culture. Bivariate comparisons show officers' levels of both general and post-OIS community trust significantly differ based on reported frequency of emotion, assessment of job satisfaction and department administration, and wider cultural context. Furthermore, multivariate analyses indicate significant factors associated with trust levels include frequency of both positive (fulfillment) and negative (frustration) emotions, satisfaction with training, and attitudes towards the importance of understanding local culture. Findings suggest the complexity of police-community relationships should be more fully explored in relation to supporting aspects of job-related mental wellness in police officers.

Occurrence and accumulation of pharmaceutical products in water and biota of urban lowland rivers.

We evaluated the distribution of eleven groups of pharmaceutically active compounds (PhACs) in surface waters and biota of different trophic levels, in five sites of two lowland urban rivers in Argentine. Twenty-nine out of 39 PhACs and two metabolites were detected in at least one water sample (2-9622 ng/L), eleven detected in biofilms (1-179 ng/g d.w.) and eight in the macrophyte Lemna gibba (4-112 ng/g d.w). The two more polluted sites had a similar distribution of the main groups of compounds. In surface waters, the largest concentrations were for the analgesic acetaminophen (9622 ng/L), the antibiotic sulfamethoxazole (326 ng/L), the antihypertensive valsartan (963 ng/L), the ß-blocking agent atenolol (427 ng/L), the diuretic hydrochlorothiazide (445 ng/L) and the psychiatric drug carbamazepine (99 ng/L). The antibiotic ciprofloxacin exhibited the highest concentration in the biofilm (179 ng/g d.w.) and in the macrophyte L. gibba (112 ng/g d.w.) Several compounds were detected in the water but not in the biota (e.g., codeine and bezafibrate), and others (e.g., azithromycin and citalopram) were found in the biota but not in the surface water. Significant bioaccumulation factors (>1000 L/kg d.w.) were obtained for venlafaxine and ciprofloxacin in biofilm. Our results show that PhACs may accumulate in several biological compartments. Within an environmental compartment, similar PhACs profile and concentrations were found in different sites receiving urban pollution. Among different compartments, biofilms may be the most suitable biota matrix to monitor the immediate reception of PhACs in the biota. Our results indicate that the presence of PhACs in urban rivers and their accumulation in the biota could be incorporated as symptoms of the urban stream syndrome.

Seizure outcome after epilepsy surgery in tuberous sclerosis complex: Results and analysis of predictors from a multicenter study.

Epilepsy surgery is recommended in selected patients with Tuberous Sclerosis Complex (TSC). However, reports on predictive factors of seizure outcome are variable. Here we report on seizure and cognitive outcome of 35 TSC patients who received surgery for refractory epilepsy in 7 Italian centers over a period of 22 years (1997-2019). The rate of seizure-free individuals at last follow-up (mean 7.5 years, range 1-21 years) was 51%. Patients with longer follow-up (≥10 years) had a lower rate of Engel I outcome (11.1%) than those who received surgery in the last 10 years (65.4%, p = 0.003). Factors associated with Engel II, III, IV outcome in our cohort included: high number of cortical tubers (≥5); presence of subependymal nodules (SENs); seizure onset before age 1 year; and multifocal interictal epileptic discharges (IEDs) on electroencephalogram (EEG). A subset of patients evaluated with Vineland Adaptive Behaviour Scales (VABS) showed developmental gains, in line with their developmental trajectories, but no improvement in standard scores after surgery was noted. Our study demonstrates that the rates of successful seizure outcome of epilepsy surgery in TSC have improved in the last 10 years. More than half of the patients achieved seizure freedom, and a high proportion of affected individuals experienced a reduction in seizure burden and in antiseizure medications. A comprehensive assessment after surgery should be performed in TSC patients to evaluate the overall neurodevelopmental outcome, as measures that are based only on seizure control do not adequately identify the benefits of surgery on global functioning in these patients.

Extending the transposable payload limit of Sleeping Beauty (SB) using the Herpes Simplex Virus (HSV)/SB amplicon-vector platform.

The ability of a viral vector to safely deliver and stably integrate large transgene units (transgenons), which not only include one or several therapeutic genes, but also requisite native transcriptional regulatory elements, would be of significant benefit for diseases presently refractory to available technologies. The herpes simplex virus type-1 (HSV-1) amplicon vector has the largest known payload capacity of approximately 130 kb, but its episomal maintenance within the transduced cell nucleus and induction of host cell silencing mechanisms limits the duration of the delivered therapeutic gene(s). Our laboratory developed an integration-competent version of the HSV-1 amplicon by adaptation of the Sleeping Beauty (SB) transposon system, which significantly extends transgene expression in vivo. The maximum size limit of the amplicon-vectored transposable element remains unknown, but previously published plasmid-centric studies have established that DNA segments longer than 6-kb are inefficiently transposed. Here, we compared the transposition efficiency of SB transposase in the context of both the HSV amplicon vector as well as the HSV amplicon plasmid harboring 7 and 12-kb transposable reporter transgene units. Our results indicate that the transposition efficiency of the 12-kb transposable unit via SB transposase was significantly reduced as compared with the 7-kb transposable unit when the plasmid version of the HSV amplicon was used. However, the packaged HSV amplicon vector form provided a more amenable platform from which the 12-kb transposable unit was mobilized at efficiency similar to that of the 7-kb transposable unit via the SB transposase. Overall, our results indicate that SB is competent in stably integrating transgenon units of at least 12 kb in size within the human genome upon delivery of the platform via HSV amplicons.

Dynamic relocalization of histone MacroH2A1 from centrosomes to inactive X chromosomes during X inactivation.

Histone variant macroH2A1 (macroH2A1) contains an NH(2)-terminal domain that is highly similar to core histone H2A and a larger COOH-terminal domain of unknown function. MacroH2A1 is expressed at similar levels in male and female embryonic stem (ES) cells and adult tissues, but a portion of total macroH2A1 protein localizes to the inactive X chromosomes (Xi) of differentiated female cells in concentrations called macrochromatin bodies. Here, we show that centrosomes of undifferentiated male and female ES cells harbor a substantial store of macroH2A1 as a nonchromatin-associated pool. Greater than 95% of centrosomes from undifferentiated ES cells contain macroH2A1. Cell fractionation experiments confirmed that macroH2A1 resides at a pericentrosomal location in close proximity to the known centrosomal proteins gamma-tubulin and Skp1. Retention of macroH2A1 at centrosomes was partially labile in the presence of nocodazole suggesting that intact microtubules are necessary for accumulation of macroH2A1 at centrosomes. Upon differentiation of female ES cells, Xist RNA expression became upregulated and monoallelic as judged by fluorescent in situ hybridization, but early Xist signals lacked associated macroH2A1. Xi acquired macroH2A1 soon thereafter as indicated by the colocalization of Xist RNA and macroH2A1. Accumulation of macroH2A1 on X chromosomes occurred with a corresponding loss of centrosomal macroH2A1. Our results define a sequence for the loading of macroH2A1 on the Xi and place this event in the context of differentiation and Xist expression. Furthermore, these results suggest a role for the centrosome in the X inactivation process.

Regulating intensity using perceived exertion: effect of exercise duration.

To examine whether the validity of perception-based intensity regulation would be affected by exercise duration, 20 subjects were recruited to complete a maximal exercise test (GXT) and four submaximal trials of varying duration and intensity using a cyle ergometer. During GXT, ratings of perceived exertion (RPE), oxygen uptake VO2, heart rate (HR), and power output (PO) equivalent to 50 and 75% VO2peak were determined. During each trial, subjects were to produce and maintain a workload using RPE estimated at 50 or 75% VO2peak for 20 or 40 min, and VO2, HR, and PO were measured throughout the exercise. No differences in average VO(2) were found between the estimation and production trial of either duration. However, average HR and PO were lower (P < 0.05) during the production trial of both durations. It appears that exercise duration has a minimal impact upon the accuracy of using RPE to regulate a target metabolic demand.

Multimeric arrays of the yeast retrotransposon Ty.

We have identified a novel integrated form of the yeast retrotransposon Ty consisting of multiple elements joined into large arrays. These arrays were first identified among Ty-induced alpha-pheromone-resistant mutants of MATa cells of Saccharomyces cerevisiae which contain Ty insertions at HML alpha that result in the expression of that normally silent cassette. These insertions are multimeric arrays of both the induced genetically marked Ty element and unmarked Ty elements. Structural analysis of the mutations indicated that the arrays include tandem direct repeats of Ty elements separated by only a single long terminal repeat. The Ty-HML junction fragments of one mutant were cloned and shown to contain a 5-base-pair duplication of the target sequence that is characteristic of a Ty transpositional insertion. In addition, the arrays include rearranged Ty elements that do not have normal long terminal repeat junctions. We have also identified multimeric Ty insertions at other chromosomal sites and as insertions that allow expression of a promoterless his3 gene on a plasmid. The results suggest that Ty transposition includes an intermediate that can undergo recombination to produce multimers.

Messenger RNAs encoding mouse histone macroH2A1 isoforms are expressed at similar levels in male and female cells and result from alternative splicing.

Two protein isoforms of histone macroH2A1 (mH2A1) are found in mammalian cells. One isoform, mH2A1.2 is highly concentrated on the heterochromatinized inactive X chromosome (Xi) of female cells. mH2A1.2 protein is also present in male cells, but fails to form dense concentrations. Another protein isoform, mH2A1.1, differs from mH2A1.2 by a single short segment of amino acids. In this study, we cloned and characterized the genomic locus of the mouse mH2A1 gene and mapped it to chromosome 13. Two alternatively spliced transcripts derived from the mH2A1 locus are responsible for the generation of the two mH2A1 protein isoforms with mH2A1.2 mRNA being the most abundant spliced form in all tissues examined. The absolute amount of mH2A1 mRNA is similar in male and female cells for most tissues with the exception of testes where it is par-ticularly abundant. Both spliced forms are present in all adult tissues analyzed as well as in female embryonic stem cells. In contrast, male embryonic stem cells expressed mH2A1.1 at low levels if at all. The relatively abundant expression of mH2A1 in both sexes suggests that mH2A1 has functions in addition to a possible involvement in X chromosome inactivation.

Evaluation of a "nude" mouse-human tumor panel as a predictive secondary screen for cancer chemotherapeutic agents.

Nine established human melanoma tissue-cultured cell lines heterotransplanted in C57BL/6 "nude" mice were exposed to each of 4 chemotherapeutic agents of known clinical activity against human melanoma. Two of the therapeutic agents, 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and 5-(3,3-dimethyl-1-triazino) imidazole-4-carboxamide (DTIC), are known to be active against human melanoma; the other two, adriamycin and 5-azacytidine, are known to be inactive. Sterile saline served as a control agent. In 2 cell line heterotransplants, the control tumor spontaneously regressed. Of the 7 cell lines that remained for evaluation, 4 were sensitive to DTIC, 1 was sensitive to BCNU, and none was sensitive to adriamycin or 5-azacytidine. These data indicate that the nude mouse-human tumor model may be a predictive secondary screen for cancer chemotherapeutic agents.

Effect of low dose cyclophosphamide on the immune system of cancer patients: depletion of CD4+, 2H4+ suppressor-inducer T-cells.

We studied peripheral blood lymphocytes (PBL) from 42 patients with metastatic melanoma undergoing treatment with cyclophosphamide (CY) plus melanoma vaccine to determine whether CY immunopotentiation could be related to depletion of T-cells that function as inducers of suppression. Every 28 days, the patients were given CY, 300 mg/m2 i.v., followed 3 days later by the intradermal injection of autologous, irradiated melanoma cells mixed with Bacillus Calmette-Guérin. PBL were separated by density gradient centrifugation and cryopreserved until needed for testing. They were stained with monoclonal antibodies directly conjugated to fluorescein isothiocyanate or phycoerythrin and analyzed by two-color flow cytometry. At no time after the initiation of CY plus vaccine were there any significant changes in the percentages of helper-inducer T-cells (CD4+), suppressor-cytotoxic T-cells (CD8+), or the subpopulation of CD8+ cells expressing Leu 15, a marker for suppressor cells. Treatment of melanoma patients with CY plus vaccine resulted in a progressive fall in the proportion of CD4+ T-cells expressing the 2H4 (CD45) antigen, which identifies inducers of suppression. The reduction of CD4+, 2H4+ T-cells did not become apparent until day 28 after the first dose of CY and reached statistical significance only on days 49 (21 days after the second dose) and 105 (21 days after the fourth dose) (mean changes +/- SE: day 49, -5.4 +/- 1.4%, P less than 0.01; day 105, -9.1 +/- 2.2%, P less than 0.01; t test for nonindependent samples). In contrast, the proportion of CD4+ T-cells expressing the antigen 4B4 (CDw29), which are true helper cells, increased slightly, although not significantly, following the institution of CY plus vaccine (mean changes: day 49, +2.9 +/- 2.1%; day 105, +3.6 +/- 2.4%). Similar results were obtained when absolute numbers of circulating cells, rather than percentages, were analyzed. Thus the number of CD4+, 2H4+ T-cells fell from a mean of 395,000/ml on day 0 to 309,000/ml on day 49 (P less than 0.01) to 256,000/ml on day 105 (P less than 0.05). The absolute number of CD4+, 4B4+ cells remained unchanged at the same time points. These changes were not due to progression of metastatic disease, since a comparison of patients with progressive metastases with those who were rendered disease free by surgery showed no significant differences in the reduction of the percentage of CD4+, 2H4+ T-cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Depletion of suppressor-cytotoxic T-lymphocytes by administration of a murine monoclonal antibody.

We administered anti-Leu 2a, a murine monoclonal antibody to the human suppressor-cytotoxic T-cell subset, to 20 patients with advanced cancer to determine the toxicity and its ability to deplete circulating Leu 2(+) lymphocytes. Four doses were tested, 1, 5, 25, and 100 mg, and the infusion rate varied from 2 to 24 h. Administration of anti-Leu 2a produced rapid (within 4 h) depletion of circulating Leu 2(+) lymphocytes, the magnitude and duration of which were dose dependent: the 1-mg dose caused a less than 50% fall in circulating Leu 2(+) lymphocytes, while the higher doses caused 75-98% depletion of those cells in 10 of 17 patients so treated. The duration of depletion of Leu 2(+) cells was 1-2 days after 5 mg of anti-Leu 2a, 3-4 days after 25 mg, and 4-30+ days after 100 mg. In seven patients (3-5, 3-25, and 1-100 mg), there was persistence of variable numbers of circulating mouse Ig-coated Leu 2(+) cells, possibly indicating impaired capacity to clear these cells. Modulation of the Leu 2a antigen after antibody treatment was not observed. Peak serum levels of anti-Leu 2a were (medians): 5-mg dose = 350 ng/ml, 25-mg dose = 5500 ng/ml, and 100-mg dose = 48,000 ng/ml; murine antibody was detectable in the serum for 7-14 days after the 100-mg dose. All patients had increased titers of antimouse antibody following treatment with peak titers on day 14. The most common toxicity was shaking chills. This occurred within 1.5 h of beginning the infusion, lasted for no more than 30 min, and did not require cessation of the treatment. Anti-Leu 2a administration caused a clinically unimportant, but statistically significant fall in hematocrit (mean = -7%) and platelet (mean = -23%) count and a transient (less than 1 day duration) fall in the total lymphocyte count. Thus, infusion of murine monoclonal anti-Leu 2a can cause substantial depletion of the suppressor-cytotoxic T-cell subset with modest toxicity.

Effect of low dose cyclophosphamide on the immune system of cancer patients: reduction of T-suppressor function without depletion of the CD8+ subset.

Low dose cyclophosphamide (CY) can augment the development of delayed-type hypersensitivity to primary antigens in patients with advanced cancer. In this paper, we have considered the hypothesis that the immunopotentiation is related to reduction of T-suppressor activity. Peripheral blood lymphocytes were collected and cryopreserved from 45 patients with metastatic malignancy before and then 3, 7, and 19 days after administration of CY, 300 mg/m2 i.v. The peripheral blood lymphocytes were tested for generation of concanavalin A-inducible suppressor activity, proliferative response to phytohemagglutinin, and phenotype using monoclonal antibodies to CD4 and CD8. Concanavalin A-inducible suppression was significantly reduced by day 3 and declined progressively through day 19. The mean percentage changes in suppression were: day 3, -23.4 +/- 6.8 (SE) (P less than 0.01); day 7, -33.1 +/- 14.3 (P = 0.052); day 19, -43.1 +/- 10.7 (P less than 0.01). In contrast, CY caused no significant changes in phytohemagglutinin proliferation (mean percentage changes: day 3, -4.7 +/- 6.1; day 7, -15.6 +/- 7.5; day 19, -5.5 +/- 8.1), indicating that the reduction in concanavalin A-inducible suppression was not merely a reflection of a general reduction in peripheral blood lymphocyte function. The total number of circulating lymphocytes was not affected by low dose CY. Moreover, flow cytometric analysis showed no significant changes in the percentage of circulating CD8+ or CD4+ T-cells or in the CD4/CD8 ratio at any time point after CY. Thus, administration of low dose CY to these patients caused impairment of nonspecific T-suppressor function without selective depletion of the CD8+ subset that is generally associated with that function. Several immunoregulatory models that are consistent with these observations are discussed.

Induction of cell-mediated immunity to autologous melanoma cells and regression of metastases after treatment with a melanoma cell vaccine preceded by cyclophosphamide.

There is considerable evidence in animal tumor systems that antitumor immunity is modulated by suppressor T-lymphocytes, and that the cytotoxic drug cyclophosphamide (CY) can abrogate that suppression. We measured the acquisition of delayed-type hypersensitivity (DTH) to autologous melanoma cells in 19 patients with metastatic malignant melanoma. The patients were treated with an autologous melanoma cell vaccine, either given alone, or given 3 days after the administration of CY, 300 mg/m2 i.v. The DTH responses of CY-pretreated patients were significantly greater than those of control (vaccine only) patients. Thus, after two vaccine treatments, the median DTH responses (mm induration) were as follows: controls, 4 mm; CY pretreated, 11 mm; P = 0.034, Mann-Whitney U test, 2-tailed. Whereas seven of eight CY-pretreated patients developed DTH to autologous melanoma cells of at least 5 mm, only two of seven controls did so (P = 0.034, Fisher's exact test). Two patients had significant antitumor responses to treatment with CY plus vaccine, consisting of complete disappearance of skin metastases and a pulmonary nodule in one, and regression of s.c. and liver metastases in the other. Both patients remain free of melanoma after 42 and 33 mo, respectively.

Flow cytometric determination of the frequency and heterogeneity of expression of human melanoma-associated antigens.

We used flow cytometry to measure the expression of human melanoma antigens on cell suspensions dissociated from metastatic masses. The objective was to study the heterogeneity between tumor samples from different patients and between different tumors excised from a single patient. Fifty-three metastases excised from 34 melanoma patients were analyzed with a panel of nine murine monoclonal antibodies (MOABs). Melanoma cells were stained by an indirect fluorescent method and analyzed on a Coulter EPICS C flow cytometer after gating to exclude tumor-infiltrating leukocytes and dead cells. The most consistently and most strongly expressed antigen was the high-molecular-weight proteoglycan (detected by the MOAB 9.2.27), which was expressed on 95% of the melanoma specimens and by a high proportion of cells within each specimen (mean +/- SE, 79.2 +/- 5.5). However, strong expression of this antigen was limited to melanoma cells that had been dissociated mechanically and was markedly diminished by exposure to collagenase. Culture of collagenase-dissociated tumor cells for 24 to 48 h resulted in reexpression of the antigen. The expression of other melanoma-associated antigens was not affected by collagenase treatment, but for these antigens there was more variability between cells from an individual tumor and between tumors from different patients. The percentage of enzyme-dissociated tumors considered positive for MOAB binding (defined as at least 10% of cells positive) and the mean +/- SE of the percentage of positive cells within a tumor were as follows: MOAB ME-9-61 (antigen, p97) = 84% + (41.2 +/- 5.4%); MOAB ME-20.4 (antigen, nerve growth factor receptor) = 40% + (18.7 +/- 5.1%); MOAB ME-24 (antigen, ganglioside GD3) = 84% + (50.8 +/- 4.8%); MOAB ME-311 (antigen, ganglioside 9-O-acetyl-GD3) = 76% + (42.5 +/- 5.1%); MOAB ME-361 (antigen, mainly ganglioside GD2) = 3% + (1.9 +/- 0.8%); MOAB 3F8 (antigen, ganglioside GD2) = 36% (10.5 +/- 3.8%); MOAB 14G2a (antigen, ganglioside GD2) = 86% + (46.0 +/- 6.7%); MOAB L243 (antigen, HLA-DR) = 56% + (22.5 +/- 5.5%). In 19 cases, we were able to compare the antigenic profiles of two tumors excised from the same patient at different times. Analysis by nonindependent t test showed no significant differences in MOAB binding between the paired tumors. Moreover, linear regression analysis indicated that there was a linear relationship, with a slope approximately = 1, between the percentage of positive cells in Tumor 1 versus Tumor 2.(ABSTRACT TRUNCATED AT 400 WORDS)