Epigenetic therapy inhibits metastases by disrupting premetastatic niches.

Cancer recurrence after surgery remains an unresolved clinical problem1-3. Myeloid cells derived from bone marrow contribute to the formation of the premetastatic microenvironment, which is required for disseminating tumour cells to engraft distant sites4-6. There are currently no effective interventions that prevent the formation of the premetastatic microenvironment6,7. Here we show that, after surgical removal of primary lung, breast and oesophageal cancers, low-dose adjuvant epigenetic therapy disrupts the premetastatic microenvironment and inhibits both the formation and growth of lung metastases through its selective effect on myeloid-derived suppressor cells (MDSCs). In mouse models of pulmonary metastases, MDSCs are key factors in the formation of the premetastatic microenvironment after resection of primary tumours. Adjuvant epigenetic therapy that uses low-dose DNA methyltransferase and histone deacetylase inhibitors, 5-azacytidine and entinostat, disrupts the premetastatic niche by inhibiting the trafficking of MDSCs through the downregulation of CCR2 and CXCR2, and by promoting MDSC differentiation into a more-interstitial macrophage-like phenotype. A decreased accumulation of MDSCs in the premetastatic lung produces longer periods of disease-free survival and increased overall survival, compared with chemotherapy. Our data demonstrate that, even after removal of the primary tumour, MDSCs contribute to the development of premetastatic niches and settlement of residual tumour cells. A combination of low-dose adjuvant epigenetic modifiers that disrupts this premetastatic microenvironment and inhibits metastases may permit an adjuvant approach to cancer therapy.

DNA methylation testing for endometrial cancer detection in urine, cervicovaginal self-samples and cervical scrapes.

Endometrial cancer incidence is rising and current diagnostics often require invasive biopsy procedures. DNA methylation marker analysis of minimally- and non-invasive sample types could provide an easy-to-apply and patient-friendly alternative to determine cancer risk. Here, we compared the performance of DNA methylation markers to detect endometrial cancer in urine, cervicovaginal self-samples and clinician-taken cervical scrapes. Paired samples were collected from 103 patients diagnosed with stage I to IV endometrial cancer. Urine and self-samples were collected at home. All samples were tested for nine DNA methylation markers using quantitative methylation-specific PCR. Methylation levels measured in endometrial cancer patients were compared to unpaired samples of 317 healthy controls. Diagnostic performances were evaluated by univariable and multivariable logistic regression analysis, followed by leave-one-out cross-validation. Each methylation marker showed significantly higher methylation levels in all sample types of endometrial cancer patients compared to healthy controls (P < .01). Optimal three-marker combinations demonstrated excellent diagnostic performances with area under the receiver operating curve values of 0.95 (95% CI: 0.92-0.98), 0.94 (0.90-0.97) and 0.97 (0.96-0.99), for endometrial cancer detection in urine, self-samples and scrapes, respectively. Sensitivities ranged from 89% to 93% at specificities of 90% to 92%. Virtually equal performances were obtained after cross-validation and excellent diagnostic performances were maintained for stage I endometrial cancer detection. Our study shows the value of methylation analysis in patient-friendly sample types for endometrial cancer detection of all stages. This approach has great potential to screen patient populations at risk for endometrial cancer.

Prenatal stress enhances NNK-induced lung tumors in A/J mice.

Children born to women who experience stress during pregnancy have an increased risk of cancer in later life, but no previous animal studies have tested such a link. We questioned whether prenatal stress (PS) in A/J mice affected the development of lung tumors after postnatal response to tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Timed-bred A/J mice were randomly assigned on gestation day 12.5 to PS by restraint for 5 consecutive days or control (no restraint). Adult offspring of control and stressed pregnancies were all treated with three NNK injections (50 mg/kg every other day) and euthanized 16 weeks later to examine their lungs. Compared with controls, PS dams exhibited significantly increased levels of plasma corticosterone, increased adrenal weights and decreased fetus weights without fetal loss. Prenatally stressed litters had a significantly higher neonatal death rate within first week of life, and surviving male and female offspring developed lung epithelial proliferations with increase multiplicity, increased area and aggressive morphology. PS also induced more advanced atypical adenomatous hyperplasia lesions. We found no difference in lung NNK-derived methyl DNA adducts, but PS did significantly enhance CD3+ T cell and Foxp3+ T cell tumor infiltration. PS significantly increases multiplicity, area of NNK-induced lung tumors and advanced morphology. PS did not affect production of NNK-derived methyl DNA adducts but did increase lymphocytic infiltration of lung tumors. To our knowledge, this is the first animal model of PS with evaluation of cancer development in offspring.

DNA methylation genome-wide analysis in remnant and primary gastric cancers.

BACKGROUND: Although primary (PGC) and remnant gastric cancers (RGC) both originate from the same gastrointestinal organ, they have very distinct clinicopathological behaviors. We hypothesized that there would be distinct differences in DNA methylation patterns that would occur during carcinogenesis of RGC and PGC, and that the differences in methylation patterns may help identify the primary factor contributing to chronic inflammation in patients with RGC. METHODS: We investigated the genome-wide DNA methylation patterns of PGC and RGC tissues from 48 patients using the Infinium HumanMethylation450 Beadchip assay. The results were validated by quantitative methylation-specific PCR (qMSP) in separate, independent cohorts. RESULTS: We found that in our training cohort of 48 patients, the most variable genes from the gastric cancer tissues identified by the Infinium HumanMethylation450 Beadchip clustered the resultant heatmap into high and low methylation groups. On multivariate analysis, PGCs contributed significantly to the high methylation group (p = 0.004, OR 12.33), which suggested that the promoter methylation status in PGC is higher than that in RGC. Supporting this conclusion was the finding that in a separate qMSP analysis in a test cohort, the EPB41L3 gene, chosen because of its high ß value on microarray analysis in the gastric cancer tissues, had significantly higher DNA promoter methylation in cancer tissues in the validation PGC tissues than in RGC. CONCLUSIONS: This study demonstrated that promoter methylation status in PGC is higher than in RGC. This result may reflect the effects of the absence of Helicobacter pylori on the reduced DNA methylation in the remnant stomach.

DREAMing: a simple and ultrasensitive method for assessing intratumor epigenetic heterogeneity directly from liquid biopsies.

Many cancers comprise heterogeneous populations of cells at primary and metastatic sites throughout the body. The presence or emergence of distinct subclones with drug-resistant genetic and epigenetic phenotypes within these populations can greatly complicate therapeutic intervention. Liquid biopsies of peripheral blood from cancer patients have been suggested as an ideal means of sampling intratumor genetic and epigenetic heterogeneity for diagnostics, monitoring and therapeutic guidance. However, current molecular diagnostic and sequencing methods are not well suited to the routine assessment of epigenetic heterogeneity in difficult samples such as liquid biopsies that contain intrinsically low fractional concentrations of circulating tumor DNA (ctDNA) and rare epigenetic subclonal populations. Here we report an alternative approach, deemed DREAMing (Discrimination of Rare EpiAlleles by Melt), which uses semi-limiting dilution and precise melt curve analysis to distinguish and enumerate individual copies of epiallelic species at single-CpG-site resolution in fractions as low as 0.005%, providing facile and inexpensive ultrasensitive assessment of locus-specific epigenetic heterogeneity directly from liquid biopsies. The technique is demonstrated here for the evaluation of epigenetic heterogeneity at p14(ARF) and BRCA1 gene-promoter loci in liquid biopsies obtained from patients in association with non-small cell lung cancer (NSCLC) and myelodysplastic/myeloproliferative neoplasms (MDS/MPN), respectively.

The epidemiology of finding a dead body: reports from inner-city Baltimore, Maryland US.

In the US, there are no national statistics on encountering a dead body, which can be viewed as a measure of community health and a stressful life event. Participants for an HIV prevention intervention targeting drug users were recruited in areas of inner-city Baltimore, Maryland. Nine hundred and fifty-one respondents, most with a history of drug use, were asked "have you ever found a dead body?" and 17.0% reported they had. Leading causes of death were: violence (37%), natural causes (22.2%), drug overdose (21.6%), accidental death (3.1%), and suicide (2.5%). In multivariate logistic models, respondents with longer history of drug use and more roles in a drug economy were more likely to be exposed to a dead body. The study results suggest that this population has a high level of experiences with mortality associated with violence and drugs. To obtain a better understanding of community health, future studies should assess not only morbidity and mortality, but also how death and illness is experienced by the community.

Myo1e overexpression in lung adenocarcinoma is associated with increased risk of mortality.

This study aims to perform a comprehensive genomic analysis to assess the influence of overexpression of MYO1E in non-small cell lung carcinoma (NSCLC) and whether there are differences in survival and mortality risk in NSCLC patients depending on both DNA methylation and RNA expression of MYO1E. The DNA methylation probe cg13887966 was inversely correlated with MYO1E RNA expression in both LUAD and LUSC subpopulations showing that lower MYO1E RNA expression was associated with higher MYO1E DNA methylation. Late stages of lung cancer showed significantly lower MYO1E DNA methylation and significantly higher MYO1E RNA expression for LUAD but not for LUSC. Low DNA methylation as well as high RNA expression of MYO1E are associated with a shorter median survival time and an increased risk of mortality for LUAD, but not for LUSC. This study suggests that changes in MYO1E methylation and expression in LUAD patients may have an essential role in lung cancer's pathogenesis. It shows the utility of MYO1E DNA methylation and RNA expression in predicting survival for LUAD patients. Also, given the low normal expression of MYO1E in blood cells MYO1E DNA methylation has the potential to be used as circulating tumor marker in liquid biopsies.

A latent class analysis of alcohol abuse and dependence symptoms among Puerto Rican youth.

The study aim was to classify youths into homogenous groups based on their symptoms of Alcohol Abuse and Dependence. An NIDA-funded cross-sectional survey was administered to 622 middle and high school students in San Juan, Puerto Rico in 2000. Latent class analysis (LCA) examined the Alcohol Abuse and Dependence symptoms. Three distinct classes of drinkers were found: low (86.0% of sample), moderate (11.7% of sample), and high (2.3% of sample) severity classes which were distinguished by differing estimated probabilities of symptom reporting. The study has implications for the diagnosis of Alcohol Abuse and Dependence among Puerto Rican youths. Limitations are also noted.

Impact of CT screening in lung cancer: Scientific evidence and literature review.

The treatment of lung cancer has improved significantly in recent years however, lung cancer remains as a leading cause of cancer-related mortality worldwide. Lung cancer screening has been explored, over the past several decades, as a means of reducing lung cancer mortality, to identify asymptomatic disease when it is potentially curable. The National Lung Screening Trial (NLST) established that low-dose computed tomography (LDCT) scans of the chest can be instrumental in reducing lung cancer mortality but the criteria for screening implemented in this trial may not be equitably sensitive across racial and sex subpopulations. Furthermore, the high false detection rate reported in this trial has raised concerns regarding overdiagnosis with LDCT alone. The aim of this review is to summarize the history of lung cancer screening trials, limitations of lung cancer screening, the impact of alternative risk prediction models in reducing disparities, and the use of biomarkers in conjunction with imaging to improve diagnostic authenticity.

A TRIzol-based method for high recovery of plasma sncRNAs approximately 30 to 60 nucleotides.

Protein functional effector sncRNAs (pfeRNAs) are approximately 30-60 nucleotides (nt), of which the extraction method from plasma has not yet been reported. Silver staining in a high-resolution polyacrylamide gel suggested that the majority of plasma sncRNAs extracted by some broadly used commercial kits were sncRNAs from 100 nt upwards. Additionally, TRIzol's protocol is for long RNA but not sncRNA recovery. Here, we report a TRIzol-based frozen precipitation method (TFP method), which shows rigor and reproducibility in high yield and quality for plasma sncRNAs approximately 30-60 nt. In contrast to the yields by the commercial kit, plasma sncRNAs extracted by the TFP method enriched more sncRNAs. We used four different pfeRNAs of 34 nt, 45 nt, 53 nt, and 58 nt to represent typical sizes of sncRNAs from 30 to 60 nt and compared their levels in the recovered sncRNAs by the TFP method and by the commercial kit. The TFP method showed lower cycle threshold (CT) values by 2.01-9.17 cycles in 38 plasma samples from 38 patients, including Caucasian, Asian, African American, Latin, Mexican, and those who were a mix of more than one race. In addition, pfeRNAs extracted by two organic-based extraction methods and four commercial kits were undetermined in 22 of 38 samples. Thus, the quick and unbiased TFP method enriches plasma sncRNA ranging from 30 to 60 nt.

Survival benefit of concomitant chemoradiation in adult supratentorial primary glioblastoma. A propensity score weighted population-based analysis.

BACKGROUND: This population study aims to assess the impact of the implementation of the original Stupp protocol on overall survival in patients with new-diagnosed supratentorial primary GBM. METHODS: The Surveillance, Epidemiology, and End Results (SEER) database was used to study the survival of histologically confirmed adult supratentorial GBM patients diagnosed between 1998 and 2016. Kaplan-Meier, and a univariate and propensity-score weighted multivariate Cox proportional hazard model adjusted for age at diagnosis, sex, race, marital status and extent of resection was used to assess the survival of patients prior to implementation of the Stupp protocol in 2005 (Pre-Stupp) and following implementation of the Stupp Protocol until 2016 (Post Stupp). RESULTS: Overall, 6390 patients satisfied inclusion exclusion criteria. Median survival times were 13 months for the Pre-Stupp and 15 months for Post-Stupp groups (P<0.001). The 1-, 2-, 5- and 10-year survival rates for the Pre-Stupp group were 51%, 18%, 5% and 2% respectively compared to 59%, 27%, 8% and 4% on the Post-Stupp group. Propensity-score weighted analysis showed a lower mortality risk for patients who underwent concomitant chemoradiation during the Post-Stupp era (HR=0.77, 95% CI 0.62-0.94). There was a 42% relative reduction in the risk of death for patients treated during the Post-Stupp era. CONCLUSIONS: This population-based propensity-score study with long-term follow-up suggests that the implementation of the Stupp protocol in 2005 had a positive impact on the survival of patients with supratentorial GBM. This "real-world" analysis validates the results of the original randomized control trial on which this protocol is based.

Surgery for early-stage lung cancer with video-assisted thoracoscopic surgery versus open thoracotomy: A narrative review.

Recommending video-assisted thoracic surgery (VATS) over open thoracotomy to patients with early-stage non-small-cell lung cancer (NSCLC) is controversial. Accordingly, we reviewed randomized comparative studies to determine the risks and benefits of VATS lobectomy. Electronic searches on PubMed with standard search terms revealed 97 comparative studies published between 1990 and 2022. Of those, only 5 were randomized controlled clinical trials (RCT) and 1 is still ongoing although initial data has been published as an abstract form. A total of 918 patients were evaluated in 5 RCT's. All studies included patients with known or suspected primary lung cancer randomized in a 1:1 ratio to VATS or thoracotomy. Between 2 studies, reports of 1-year, 3-year and 5-year overall survival were found to be similar across surgical modalities. Additionally, no differences were found in the rates of locoregional and distant recurrence. Three studies reported no statistical differences in the number of hilar and mediastinal lymph nodes sampled. Two studies found decreased length of stay following VATS (4 days v 5 days, P = 0.027 and P = 0.008), while 2 found no difference. Increased in-hospital complications were seen in 2 studies (P = 0.008 and P = 0.039). VATS was associated with decreased pain scores, better self-reported QOL at 52 weeks (P = 0.014). Few randomized clinical trials comparing VATS lobectomy to open thoracotomy and lobectomy in early stage NSCLC have been reported. These studies suggest that VATS lobectomy offers similar outcomes with decreased in-hospital complications, pain, length of stay, and improved physical functioning when compared to thoracotomy.

A murine xenograft model of spontaneous metastases of human lung adenocarcinoma.

BACKGROUND: The flank is commonly used for primary xenografts in mice, but it is rare for these tumors to metastasize. Tail vein injection creates a pattern of metastases, but is artificial. We hypothesized that the liver is a convenient alternative xenograft site and that metastases would gradually proceed spontaneously. MATERIALS AND METHODS: Using 15 NOD.CB17-Prkdc(scid)/NcrCrl (NOD/SCID) mice, 10,000 A549 cells were xenografted into the liver while a second group of five mice were xenografted in the flank with 100,000 A549 cells as a control. Mice were euthanized and grossly dissected at 7 wk. A third group of seven mice received liver xenografts with A549 and a mouse each week was euthanized for 7 wk and evaluated. The liver, lung, and spleen were examined histologically. RESULTS: At 7 wk, 15/15 liver xenografted mice had gross primary tumor in the liver. Histologic review confirmed multiple microscopic foci of metastatic disease in all mice (15/15) throughout the lungs, mediastinal nodes, and spleen. The control group had primary tumor in the flank (4/5), but none had histologic evidence of metastases. Serially euthanized liver xenografted mice revealed evidence of a gradual spontaneous metastatic model system with the first histologic findings of micrometastases appearing in the lungs by wk 5, which became wide spread by wk 7. Splenic and mediastinal lymph node metastases developed in wk 6 and 7. CONCLUSIONS: Liver xenografting of A549 cells into NOD/SCID mice is a reliable way of developing widespread micrometastases. This model allows the study of a gradually developing solid tumor with subsequent metastatic spread.

Factors related to past HIV testing among South African non-injection drug users.

South Africa has some of the highest estimates of human immunodeficiency virus (HIV) in the world, with a prevalence of 21.5%. Despite this, based on population-level data, 39% of sexually active South Africans have never been tested for HIV. Non-injection drug users (NIDUs) are a high-risk and increasingly prevalent group in South Africa. However, few studies have examined HIV test utilization among high-risk groups such as drug users in South Africa. The study was conducted in Pretoria, South Africa between 2002 and 2006. Of the 382 individuals surveyed, 31% had been tested for HIV in the past. Results indicate that females and older individuals were significantly more likely to have been tested for HIV at some point in the past, while individuals who did not know someone with HIV/AIDS as well as individuals who are unsure of their risk of HIV infection were significantly less likely to have ever accessed testing. Identification of these subgroups has implications for the development of targeted interventions to promote greater HIV testing among at-risk groups in South Africa.

Sexual networks and housing stability.

Unstable housing is related to a range of health problems including substance abuse, poor mental health, and HIV. Little is known about how sexual partners' attributes influence access to resources such as housing. The purpose of the present study was to examine the relationship between sexual network characteristics and improvements in housing situation among a sample of drug users using a longitudinal design. Size of one's sex network was not associated with housing change. However, having a main partner and having a sex partner who lent money was associated with moving from a homeless state at baseline to being housed at follow-up. Also, having a sex partner who was a drug user was associated with decrease in the odds of improving one's housing situation.

Alcohol, Drug and Sexual Risk Behavior Correlates of Recent Transactional Sex Among Female Black South African Drug Users.

Transactional sex among black South African women has become a mode of economic survival putting them at higher risk for HIV and other infectious disease. In order to inform HIV interventions, drug and sexual risk behavior correlates of recent transactional sex among a descriptive epidemiological, cross-sectional sample of 189, black, South African women in Pretoria were examined using log binomial regression. Prevalence of HIV seropositivity was extremely high among non-transactional sex workers (47.1%) and transactional sex workers (54.6%), albeit not significantly different. Adjusted regression results indicated that the probability of transactional sex was greater for drug using women who tested positive for cocaine use (Adjusted Prevalence Ratio (APR)=1.3, 95% CI=1.1, 1.5) and knew of anyone who died of AIDS (APR =1.5, 95% CI 1.1, 2.1). The probability of transactional sex was lower for female drug users who reported greater education (APR =0.6, 95% CI= 0.4, 0.8), condom use in their first sexual encounter (APR =0.7, 95% CI=0.6, 1.0) or reported a recent steady sexual partnership (APR =0.8, 95% CI=0.7, 0.9). Drug use-related interventions for female transactional sex workers may need to focus on methods for the reduction of not only drug use, especially cocaine use, but also the reduction of sexual risk behaviors.

Severe Psychiatric Symptoms in a Patient With EGFR Exon-20 Insertion Mutation Receiving Mobocertinib: A Case Report.

Tyrosine kinase inhibitor therapy is an established standard of care for patients with NSCLC with EGFR mutations, but a worse prognosis has been observed in patients with specific EGFR exon-20 insertion mutations. Mobocertinib (TAK-788) is a novel tyrosine kinase inhibitor developed to target EGFR exon-20 insertion and has exhibited promising response rates and acceptable safety in phase 1 and 2 trials. We report a case of a 59-year-old woman with metastatic NSCLC and EGFR exon-20 mutation responsive to mobocertinib therapy, who developed severe depression and catatonia approximately 4 months after mobocertinib initiation, ultimately necessitating its permanent discontinuation. Given the observed severe depression in this case report, we recommend that, for patients on mobocertinib who develop neuropsychiatric adverse effects, strong consideration should be given for dose interruption or discontinuation.

Socioeconomic Disparities in Non-Small Cell Lung Cancer With Brain Metastases at Presentation: A Population-Based Study.

OBJECTIVE/BACKGROUND: The purpose of this study was to characterize the impact of household income disparities in the survival of patients with non-small cell lung cancer (NSCLC) presenting with brain metastasis on a population-based level. METHODS: This is a population-based cohort study using the Surveillance, Epidemiology, and End Results (SEER) database from 2010-2016 including 15,808 NSCLC patients presenting with brain metastasis. RESULTS: This study comprises 15,808 adult patients with NSCLC presenting with brain metastases having an age range 64 ± 10 years with 51% male, 76% white, 52% married, 61% insured, and with 85% of lung adenocarcinoma histopathology. The 1-, 2- and 5-year survival rates for living in the lower household income quartile were 21%, 10%, and 3%, respectively, for the second quartile 24%, 10%, and 3%; for the third quartile 28%, 14%, and 4%; and for the top quartile 31%, 17%, and 4%, respectively. Multivariate Cox proportional hazard analysis showed that living in a higher quartile household income county is associated with increased survival (P < 0.0001), hazard ratio 0.87, 95% confidence interval (0.82-0.92). CONCLUSIONS: This population-based study suggests that living in higher median household income counties is associated with increased survival time and reduced risk of mortality for patients with NSCLC who have brain metastases present at diagnosis, independent of other factors. These findings underscore the importance of ensuring adequate and easy access to care for all patients, irrespective of their economic background.

Clinical Significance of Plasma CD9-Positive Exosomes in HIV Seronegative and Seropositive Lung Cancer Patients.

Recently, the role of exosomes in the progression of both cancer and HIV (human immunodeficiency virus) has been described. This study investigates the clinical significance of CD9-positive plasma exosomes in lung cancer patients, healthy individuals, and HIV-positive patients with or without lung cancer. Using a verified with transmission electron microscopy double-sandwich ELISA technique, plasma-derived exosomes were isolated and quantified from 210 lung cancer patients (including 44 metastatic patients with progressive disease after chemotherapy), 49 healthy controls, 20 patients with pulmonary granulomas, 19 HIV+ patients with lung cancer, 31 HIV+ patients without cancer, and 3 HIV+ patients with pulmonary granulomas. Plasma exosome concentrations differed between healthy controls, patients with immunocompetent pulmonary granulomas and patients with lung cancer even after chemotherapy (p < 0.001). Lung cancer patients after chemotherapy had lower exosome concentrations compared to patients with untreated lung cancer or granuloma (p < 0.001 for both). HIV+ patients without lung cancer had significantly higher exosome concentrations compared to HIV+ patients with lung cancer (p = 0.016). Although exosome concentrations differed between all different lung cancer histologies and healthy controls (p < 0.001 for all histologies), adjusted statistical significance was oµy retained for patients with granulomas and SCLC (Small-cell lung cancer, p < 0.001). HIV-induced immunodeficient patients with or without lung cancer had lower plasma exosomes compared to immunocompetent granuloma and lung cancer patients (p < 0.001). Finally, higher plasma exosomes were associated both on univariate (p = 0.044), and multivariate analysis (p = 0.040) with a better 3-year survival in stage II and III NSCLC (Non-small-cell lung carcinoma) patients. In conclusion, our study shows that CD9-positive plasma exosomes are associated with both lung cancer and HIV, prior chemotherapy, as well as with survival, suggesting a possible prognostic value.

Factors associated with recruiting an HIV seropositive risk network member among injection drug users.

Using a social network approach to recruitment, we analyzed the factors that predicted recruitment of an HIV seropositive network member by active injection drug users (IDUs). IDUs were asked to bring in drug and sex network members, whom they delineated on a social network inventory. The 297 index participants recruited 425 networks, of whom 17.3% were seropositive. The majority of seropositive members were recruited by IDUs who reported no seropositive risk network members. The strongest predictor of recruiting seropositives was ethnicity, with African American indexes more than 3 times more likely than others to recruit seropositives as compared to other ethnic groups. Those African American indexes who reported that they had no seropositive network members were over 10 times more likely to recruit a seropositive. These results suggest the feasibility to target active drug users to recruit seropositives and emphasize the public health importance of focusing network approaches on the networks of African American IDUs.