Update on pathology laboratory development and research in advancing regional cancer care in Malawi.

The pathology laboratory at Kamuzu Central Hospital (KCH) in Lilongwe, Malawi was established in 2011. We published our initial experiences in laboratory development and telepathology in 2013 and 2016, respectively. The purpose of this paper is to provide an update on our work by highlighting the positive role laboratory development has played in improving regional cancer care and research. In addition, we provide a summary of the adult pathology data from specimens received between July 1, 2011, and May 31, 2019, with an emphasis on malignant diagnoses. We compare these summaries to estimates of cancer incidence in this region to identify gaps and future needs.

Safety, efficacy, and affordability of ABVD for Hodgkin lymphoma in Malawi: a prospective cohort study.

Background: ABVD (doxorubicin, bleomycin, vinblastine, and dexamethasone) is a proven, curative regimen for Hodgkin lymphoma (HL). Prospective data describing HL treatment in sub-Saharan Africa are limited. We aimed to fill this knowledge gap, using data from Malawi. Methods: We report a prospective observational cohort of HL (aged ≥ 15) from a single, tertiary referral centre in Malawi. We enrolled patients with pathologicially confirmed Hodgkin lymphoma between June 1, 2013, and Dec 31, 2021 with follow-up censored on May 31, 2022. Patients were treated with ABVD and concurrent antiretroviral therapy if HIV-positive and were followed up for 5 years. The primary outcome was overall survival; secondary outcomes included progression-free survival, response assessment, and adverse events. Microcosting of HL diagnosis, treatment, and follow-up was embedded. Findings: We enrolled 38 patients with a median age of 27 years (interquartile range 19-46); eleven (28%) were HIV-positive. Of 35 patients treated with ABVD, 24 (71%) had stage III/IV, nine (26%) unfavourable limited stage, and two (6%) favourable limited stage. Among HIV-infected individuals, mean CD4 count at HL diagnosis was 179 cells/uL and ten (91%) had HIV RNA < 400 copies/mL. Grade 3/4 neutropenia occurred in 24 (68%) patients and caused treatment delay in 16 (46%). Of ten deaths, seven were due to HL, two possible treatment-related toxicity, and one uncertain. 2-year overall survival was 82% (95% CI 70-96%) and 2-year progression-free survival was 64% (95% CI 50-83%). PFS appeared better for HIV-positive patients (HR 0.23 (95% CI 0.05-1.02)) after controlling for stage and performance status (p = 0.05). We estimated $2708 (2022 USD) for HL diagnosis, treatment, and follow-up in our cohort. Interpretation: Our findings suggest that treatment with ABVD is safe, efficacious, and affordable for HL in Malawi. Outcomes are worse than in high-income countries due to HL progression. Future studies are needed to understand outcome inequities and to assess efficacy of therapies for patients with relapsed or refractory HL in Malawi. Funding: National Institutes of Health, Lineberger Comprehensive Cancer Center.

Cancer-Related Stigma in Malawi: Narratives of Cancer Survivors.

PURPOSE: Stigma is an impediment across the cancer care continuum, leading to delayed presentation to care, elevated morbidity and mortality, and reduced quality of life. The goal of this study was to qualitatively examine the drivers, manifestations, and impacts of cancer-related stigma among individuals who received cancer treatment in Malawi, and to identify opportunities to address stigma. METHODS: Individuals who had completed treatment for lymphoma (n = 20) or breast cancer (n = 9) were recruited from observational cancer cohorts in Lilongwe, Malawi. Interviews explored the individual's cancer journey, from first symptoms through diagnosis, treatment, and recovery. Interviews were audio-recorded and translated from Chichewa to English. Data were coded for content related to stigma, and thematically analyzed to describe the drivers, manifestations, and impacts of stigma along the cancer journey. RESULTS: Drivers of cancer stigma included beliefs of cancer origin (cancer as infectious; cancer as a marker of HIV; cancer due to bewitchment), perceived changes in the individual with cancer (loss of social/economic role; physical changes), and expectations about the individual's future (cancer as death sentence). Cancer stigma manifested through gossip, isolation, and courtesy stigma toward family members. The impacts of cancer stigma included mental health distress, impediments to care engagement, lack of cancer disclosure, and self-isolation. Participants suggested the following programmatic needs: community education about cancer; counseling in health facilities; and peer support from cancer survivors. CONCLUSION: The results highlight multifactorial drivers, manifestations, and impacts of cancer-related stigma in Malawi, which may affect success of cancer screening and treatment programs. There is a clear need for multilevel interventions to improve community attitudes toward people with cancer, and to support individuals along the continuum of cancer care.

Case report: Multicentric Castleman disease as a manifestation of immune reconstitution inflammatory syndrome in Malawi.

Introduction: Multicentric Castleman disease (MCD) is a lymphoproliferative disorder characterized by systemic inflammation, lymphadenopathy, and cytopenias. MCD caused by Kaposi sarcoma herpesvirus (MCD-KSHV) frequently arises in the context of HIV. It can be associated with immune reconstitution inflammatory syndrome (IRIS), but MCD-IRIS is rarely reported in sub-Saharan Africa (SSA) where HIV and KSHV infection are common. Case description: A 36-year-old woman in Malawi with HIV on antiretroviral therapy (ART) for nine years presented with fatigue, weight loss, and lymphadenopathy. Lymph node biopsy was consistent with HIV lymphadenitis without evident KSHV-MCD and HIV RNA was 4,244 copies/mL. She switched to second-line ART and returned four months later with worsening lymphadenopathy, fever, night sweats, weight loss, and anemia. A repeat lymph node biopsy demonstrated unequivocal KSHV-MCD features not present on the original biopsy. Her repeat HIV viral load was undetectable and she received chemotherapy with subsequent remission on continued ART for 24 months. Discussion: This is among the first reported cases of MCD-IRIS from SSA, which has implications for a region where HIV and KSHV are highly prevalent. MCD-IRIS may contribute to early mortality after ART initiation in SSA, and increased awareness alongside improved diagnostic and treatment capacity are needed.

Clinical Characteristics and Outcomes of Acute Lymphoblastic Leukemia in Adolescents and Young Adults in Malawi.

PURPOSE: There are limited data on treatment and outcomes for acute lymphoblastic leukemia (ALL) among adolescents and young adults in sub-Saharan Africa. We describe a prospective observational cohort in Malawi. METHODS: Patients age 15-39 years with newly diagnosed ALL at Kamuzu Central Hospital, Malawi, were enrolled from 2013 to 2019; follow-up was censored on December 2020. ALL diagnosis was confirmed on-site using immunohistochemistry and telepathology consultation involving pathologists in Malawi and the United States. All but four patients were treated with a modified pediatric-inspired regimen (Cancer and Leukemia Group B 10403 protocol). Key modifications included omission of asparaginase and no dose escalation for methotrexate. RESULTS: Of 19 participants, the median age was 22 (range 15-36) years. Of the 15 patients who initiated treatment, 11 (73%) achieved remission after induction, one (7%) died during induction, two (13%) had refractory disease, and one (7%) absconded. No patients were lost to follow-up. Eventually, 10 of 11 patients (91%) with confirmed remission relapsed. The median duration of first remission was 10 (range 3-22) months. Twelve of 15 treated patients (80%) had died at the time of censoring. Among treated patients, the 12- and 24-month overall survival was 50% (95% CI, 23 to 72) and 17% (95% CI, 3 to 42), respectively. CNS involvement was associated with worse survival. CONCLUSION: It is possible to treat adolescents and young adults with ALL in low-resource settings using a low-cost, pediatric-inspired regimen; however, outcomes are poor. Both cost and limitations in supportive care infrastructure limit intensive cytotoxic approaches such as asparaginase. Patient-reported outcomes are needed to understand the quality of life and cost-effectiveness. Critically, innovative, leap-frog therapies, such as monoclonal or bispecific antibodies, and feasible economic models for resource-limited settings are urgently needed.

Comparison of best supportive care, CHOP, or R-CHOP for treatment of diffuse large B-cell lymphoma in Malawi: a cost-effectiveness analysis.

BACKGROUND: Cost-effectiveness data for cancer treatment are needed from sub-Saharan Africa, where diffuse large B-cell lymphoma (DLBCL) is a common, curable cancer. In high-income countries, the standard of care for DLBCL is R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) chemoimmunotherapy. Rituximab is often not available in sub-Saharan Africa due to perceived unaffordability, and treatment with CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) is common. We aimed to evaluate the cost-effectiveness of treatment in Malawi, comparing best supportive care, CHOP, or R-CHOP in patients with DLBCL. METHODS: For this cost-effectiveness analysis, we used published Malawi microcosting data, clinical data from a prospective cohort treated with CHOP, and clinical trial data evaluating R-CHOP. We used a decision-tree model to calculate costs per disability-adjusted life-year (DALY) averted from the health system perspective for the treatment of patients with DLBCL with best supportive care, CHOP, or R-CHOP, running the model on a per-patient basis and a Malawi population-level basis. We used the WHO definitions of cost-effective (three times the GDP per capita of the country) and extremely cost-effective (equal to the GDP per capita of the country) as willingness-to-pay thresholds for Malawi. FINDINGS: On a per-patient level, compared with best supportive care, CHOP was estimated to avert a mean 7·4 DALYs at an incremental cost of US$1384, for an incremental cost-effectiveness ratio (ICER) of $189 per DALY averted, which is substantially lower than the willingness-to-pay threshold (extremely cost-effective). Compared with CHOP, R-CHOP was estimated to avert 2·8 DALYs at an incremental cost of $3324, resulting in an ICER of $1204 per DALY averted, which is slightly higher than the cost-effective willingness-to-pay threshold. In probabilistic sensitivity analyses, CHOP remained cost-effective for DLBCL treatment in more than 99% of simulations, whereas R-CHOP was lower than the threshold in 46% of simulations. INTERPRETATION: We estimated CHOP to be cost-effective for DLBCL treatment in Malawi, and that the addition of rituximab might be cost-effective. Despite upfront costs, DLBCL treatment is probably a prudent investment relative to other accepted health interventions in sub-Saharan Africa. FUNDING: National Institutes of Health.

Safety and efficacy of rituximab in patients with diffuse large B-cell lymphoma in Malawi: a prospective, single-arm, non-randomised phase 1/2 clinical trial.

BACKGROUND: There are no clinical trials involving patients with diffuse large B-cell lymphoma (DLBCL) in sub-Saharan Africa since antiretroviral therapy (ART) for HIV became widely available in this region. We aimed to establish the safety and efficacy of rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) in patients with DLBCL in Malawi. METHODS: This prospective, single-arm, non-randomised phase 1/2 clinical trial was done at Kamuzu Central Hospital Cancer Clinic (Lilongwe, Malawi). Eligible patients were adults (aged 18-60 years) with newly diagnosed DLBCL, an Eastern Cooperative Oncology Group performance status of 0-2, a CD4 count of 100 cells per µL or higher (if HIV-positive), measurable disease by physical examination, an absolute neutrophil count of 1000 × 109 cells per L or higher, a platelet count of 100 × 109 platelets per L or higher, a serum creatinine concentration of 132·60 µmol/L or less, a total bilirubin concentration of 34·21 µmol/L or less, a negative urine pregnancy test in women of childbearing potential, and no previous cytotoxic therapy. Pregnant or breastfeeding women, and individuals with CNS involvement from DLBCL, chronic hepatitis B infection (unless they were receiving tenofovir plus lamivudine), or any other comorbidities that would compromise the protocol objectives were excluded. Eligible patients received intravenous rituximab 375 mg/m2, cyclophosphamide 750 mg/m2, doxorubicin 50 mg/m2, and vincristine 1·4 mg/m2 (maximum 2 mg/m2), and oral prednisone 100 mg or an equivalent drug every 21 days for up to six cycles. HIV-positive patients received concurrent ART. The primary outcome was the proportion of patients with National Cancer Institute Common Terminology Criteria for Adverse Events grade 3 or 4 non-haematological toxic effects or treatment-related deaths after six cycles of treatment. Secondary efficacy outcomes included the proportion of patients with a complete response after six cycles of treatment, and progression-free survival and overall survival at 12 months and 24 months. This trial is registered with ClinicalTrials.gov, NCT02660710. FINDINGS: Between Aug 1, 2016, and July 31, 2019, 76 patients were screened, of whom 37 were eligible for the study and received R-CHOP. The median age of patients was 44 years (IQR 39-49) and 16 (43%) were women. Of all 37 patients, 20 (54%) had stage III or IV DLBCL, and the age-adjusted international prognostic index was 2 or higher in 25 (68%) patients. 27 (73%) patients were HIV-positive, with a median CD4 count of 208 cells per µL (IQR 144-422), and 21 (78%) patients were receiving ART at enrolment. Patients completed a median of six cycles (IQR 4-6). Grade 3 or 4 non-haematological toxic effects were reported in 12 (32% [95% CI 19-49]) patients, the most common of which was infection (nine [24%] patients). Of 16 (43%) deaths, ten were due to progression of DLBCL, four were due to treatment-related complications, and two were due to other causes, yielding a treatment-related mortality of 11% (95% CI 4-26%). Grade 3 or 4 neutropenia was observed in 26 (70%) patients, and grade 3 or 4 anaemia was observed in 11 (29%) patients. A total of 22 (59%) patients had a complete response. Overall survival was 68% (95% CI 50-80) at 12 months and 55% (37-70) at 24 months, and progression-free survival was 59% (42-73) at 12 months and 53% (35-68) at 24 months. INTERPRETATION: R-CHOP could be feasible, safe, and efficacious in patients with DLBCL in Malawi. This is the first completed clinical trial on DLBCL focused on sub-Saharan African populations. Given the paucity of data on treatment of DLBCL from this region, these results could inform emerging cancer treatment programmes in sub-Saharan Africa. FUNDING: The University of North Carolina Lineberger Comprehensive Cancer Center.

Feasibility of upfront mobile money transfers for transportation reimbursement to promote retention among patients receiving lymphoma treatment in Malawi.

BACKGROUND: Cancer outcomes in sub-Saharan Africa (SSA) remain suboptimal, in part due to poor patient retention. Many patients travel long distances to receive care, and transportation costs are often prohibitively expensive. These are well-known and established causes of delayed treatment and care abandonment in Malawi and across SSA. METHODS: We sent visit reminder texts and offered upfront money to cover transportation costs through a mobile money transfer (MMT) platform to lymphoma patients enrolled in a prospective cohort in Malawi. The primary aim was to test the feasibility of upfront MMTs. RESULTS: We sent 1034 visit reminder texts to 189 participating patients. Of these texts, 614 (59%) were successfully delivered, with 536 (52%) responses. 320/536 (60%) MMTs were sent to interested patients and 312/320 (98%) came to their appointment on time. Of 189 total patients, 120 (63%) were reached via text and 84 (44%) received MMTs a median of three times (IQR 2-5). Median age of reachable patients was 41 (IQR 30-50), 75 (63%) were male, 62 (52%) were HIV+ and 79 (66%) resided outside of Lilongwe. CONCLUSION: MMTs were a feasible way to cover upfront transportation costs for patients reachable via text, however many of our patients were unreachable. Future studies exploring barriers to care, particularly among unreachable patients, may help improve the efficacy of MMT initiatives and guide retention strategies throughout SSA.

Epidemiology of haematological malignancies in people living with HIV.

People living with HIV or AIDS are at increased risk of Hodgkin and non-Hodgkin lymphoma compared with HIV-negative individuals. Data on the risk of multiple myeloma or leukaemia are inconsistent and of low quality but the risk does not seem to be increased. Specific haematological malignancies occur in different contexts of age, CD4 cell count, HIV control, viral co-infections, or chronic inflammation, and the expansion of combination antiretroviral therapy has led to varied demographic and epidemiological shifts among people with HIV. Increased use of combination antiretroviral therapy has substantially reduced the risks of diffuse large B-cell lymphoma, Burkitt lymphoma, and primary CNS lymphoma, and to a lesser extent, Hodgkin lymphoma. There is no effect of combination antiretroviral therapy use on multiple myeloma or leukaemia. Although many cases of HIV are in low-income and middle-income countries, high-quality epidemiological data for haematological malignancies from these regions are scarce. Closing this gap is an essential first step in decreasing mortality from HIV-associated haematological malignancies worldwide. Finally, although multicentric Castleman disease is not a neoplastic condition, it is an emerging precursor to neoplastic high-grade B-cell lymphoproliferation among people with HIV, especially for individuals on long-term combination antiretroviral therapy with well controlled HIV.

Modified EPOCH for high-risk non-Hodgkin lymphoma in sub-Saharan Africa.

Aggressive non-Hodgkin lymphoma (NHL) is among the most common cancers in sub-Saharan Africa (SSA), where CHOP is standard treatment and outcomes are poor. To address this, we treated 17 newly diagnosed adult patients in Malawi with Burkitt (n = 8), plasmablastic (n = 8), and primary effusion lymphoma (n = 1) with a modified EPOCH regimen between 2016 and 2019. Twelve patients (71%) were male and the median age was 40 years (range 16-63). Eleven (65%) were HIV infected, median CD4 count was 218 cells/µL (range 9-460), and nine (82%) had suppressed HIV RNA < 400 copies/mL. Patients received a median of six cycles (range 2-8) and median follow-up was 14 months (range 2-34) among patients still alive. Grade 3/4 neutropenia was observed in 26% of cycles and in 65% of patients. Sixteen (94%) responded to EPOCH and 10 (59%) achieved a complete response. One-year overall survival (OS) was 62% (95% confidence interval [CI], 42%-91%). Five patients (29%) died from progressive NHL and three (18%) from treatment-related complications. These data suggest EPOCH with setting-appropriate modifications may be a practical, safe, and effective option for improving high-risk NHL outcomes in Malawi and comparable settings, which deserves further prospective evaluation.

Microcosting Analysis of Diffuse Large B-Cell Lymphoma Treatment in Malawi.

PURPOSE: To describe the cost of treating diffuse large B-cell lymphoma (DLBCL) in Malawi under the following circumstances: (1) palliation only, (2) first-line cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP), (3) salvage etoposide, ifosfamide, and cisplatin (EPIC), and (4) salvage gemcitabine and oxaliplatin (GEMOX). METHODS: We conducted a microcosting analysis from the health system perspective in the context of a prospective cohort study at a national teaching hospital in Lilongwe, Malawi. Clinical outcomes data were derived from previously published literature from the cohort. Cost data were collected for treatment and 2-year follow-up, reflecting costs incurred by the research institution or referral hospital for goods and services. Costs were collected in Malawian kwacha, inflated and converted to 2017 US dollars. RESULTS: On a per-patient basis, palliative care alone cost $728 per person. Total costs for first-line treatment with CHOP chemotherapy was $1,844, of which chemotherapy drugs made up 15%. Separate salvage EPIC and GEMOX cost $2,597 and $3,176, respectively. Chemotherapy drugs accounted for 30% of EPIC and 47% of GEMOX. CONCLUSION: To our knowledge, this is among the first published efforts to characterize detailed costs of cancer treatment in sub-Saharan Africa. The per-patient cost of first-line treatment of DLBCL in Malawi is low relative to high-income countries, suggesting that investments in fixed-duration, curative-intent DLBCL treatment may be attractive in sub-Saharan Africa. Salvage treatment of relapsed/refractory DLBCL costs much more than first-line therapy. Formal cost-effectiveness modeling for CHOP and salvage treatment in the Malawian and other low-resource settings is needed to inform decision makers about optimal use of resources for cancer treatment.

Prospective study of Burkitt lymphoma treatment in adolescents and adults in Malawi.

Burkitt lymphoma (BL) is common in sub-Saharan Africa (SSA). In high-income countries, BL is highly curable with chemotherapy. However, there are few prospective studies from SSA describing nonpediatric BL and no regional standard of care. Thirty-five participants age 15 years or older with newly diagnosed BL were enrolled in Malawi from 2013 to 2018. Chemotherapy was administered according to institutional guidelines, with concurrent antiretroviral therapy if HIV infected. Median age was 21 years (range, 15-61) and 15 participants (43%) were HIV infected. Twenty-seven participants (77%) had stage III to IV disease, and 19 (54%) had Eastern Cooperative Oncology Group performance status >1. Among HIV-infected participants, median CD4 count was 130 (range, 29-605) and 10 (67%) had suppressed HIV viral load. Four participants (11%) died before receiving chemotherapy. First-line chemotherapy consisted of: cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) (n = 22 [71%]); infusional etoposide, prednisolone, vincristine, cyclophosphamide, and doxorubicin (n = 4 [13%]); high-dose methotrexate-based chemotherapy (n = 4 [13%]); and rituximab plus CHOP (n = 1 [3%]). Among 28 evaluable participants, 14 (50%) achieved a complete response. Median overall survival (OS) was 7 months; 1-year OS was 40% (95% confidence interval [CI], 24%-56%). Sixteen (73%) of 22 deaths were a result of disease progression. Compared with CHOP, more intensive chemotherapy was associated with decreased mortality (hazard ratio, 0.24; 95% CI, 0.05-1.02; P = .05). This is among the best characterized prospective cohorts of nonpediatric BL in SSA. Most deaths resulted from progressive BL. Patients who received more intensive therapy seemed to have better outcomes. Defining optimal approaches is an urgent priority in SSA.

Mature outcomes and prognostic indices in diffuse large B-cell lymphoma in Malawi: a prospective cohort.

Outcomes for diffuse large B-cell lymphoma (DLBCL) in sub-Saharan Africa (SSA) are poorly described. We report mature data from one of the first prospective SSA cohorts. Patients aged ≥18 years with DLBCL were enrolled in Malawi 2013-2017. Participants were treated with CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) chemotherapy and concurrent antiretroviral therapy (ART) if positive for human immunodeficiency virus (HIV+). Eighty-six participants (mean age 47 years, standard deviation 13) were enrolled: 54 (63%) were male and 51 (59%) were HIV+, of whom 34 (67%) were on ART at DLBCL diagnosis. Median CD4 count was 0·113 cells × 109 /l (interquartile range [IQR] 0·062-0·227) and 25 (49%) had HIV viral load <400 copies/µl. Participants received median six cycles CHOP (IQR 4-6). No patients were lost to follow-up and the 2-year overall survival was 38% (95% confidence interval 28-49). In multivariable analyses, Eastern Cooperative Oncology Group performance status (PS) ≥2 and lactate dehydrogenase (LDH) >2× upper limit of normal (ULN) were associated with mortality. HIV status was not associated with mortality. A simplified prognostic model of LDH >2× ULN and PS ≥2 performed at least as well as the age-adjusted International Prognostic Index. DLBCL can be successfully treated in SSA and outcomes did not differ by HIV status. A simplified prognostic model prognosticates well and may be easier to use in resource-limited settings but requires validation.

Plasmablastic lymphoma in Malawi.

Plasmablastic lymphoma (PBL) clinical descriptions are scarce from sub-Saharan Africa (SSA) where both HIV and EBV are highly endemic. We identified 12 patients with pathologically confirmed PBL from a prospective cohort in Lilongwe, Malawi. Median age was 46 (range 26-71), seven (58%) were male, and six (50%) were HIV-positive. Eight patients were treated with CHOP and four with a modified EPOCH regimen. One-year overall survival was 56% (95% CI 24-79%), without clear differences based on HIV status. PBL occurs in Malawi in HIV-positive and HIV-negative individuals and can be treated successfully with curative intent, even in a low-resource setting in SSA.

Association between serum concentrations of hypoxia inducible factor responsive proteins and excessive erythrocytosis in high altitude Peru.

Painschab, Matthew S., Gary E. Malpartida, Victor G. Davila-Roman, Robert H. Gilman, Todd M. Kolb, Fabiola Leon-Velarde, J. Jaime Miranda, and William Checkley. Association between serum concentrations of hypoxia inducible factor responsive proteins and excessive erythrocytosis in high altitude Peru. High Alt Med Biol 16:26-33, 2015.-Long-term residence at high altitude is associated with the development of chronic mountain sickness (CMS), which is characterized by excessive erythrocytosis (EE). EE occurs under chronic hypoxia, and a strongly selected mutation in hypoxia-inducible factor 2α (HIF2A) has been found in native Tibetans that correlates with having a normal hemoglobin at high altitude. We sought to evaluate differences in plasma levels of four HIF-responsive proteins in 20 participants with EE (hemoglobin >21 g/dL in men and >19 in women) and in 20 healthy, age- and sex-matched participants without EE living at high altitude in Puno, Peru. We performed ELISA to measure plasma levels of the four HIF-responsive proteins: vascular endothelial growth factor (VEGF), soluble VEGF receptor 1 (sVEGF-R1), endothelin-1, and erythropoietin. As a secondary aim, we evaluated the association between HIF-responsive proteins and echocardiography-estimated pulmonary artery systolic pressure (PASP) in a subset of 26 participants. sVEGF-R1 was higher in participants with vs. without EE (mean 107 pg/mL vs. 90 pg/mL; p=0.007). Although plasma concentrations of endothelin-1, VEGF, and erythropoietin were higher in participants with vs. without EE, they did not achieve statistical significance (all p>0.25). Both sVEGF-R1 (p=0.04) and erythropoietin (p=0.04) were positively associated with PASP after adjustment for age, sex, and BMI. HIF-responsive proteins may play a pathophysiological role in altitude-related, chronic diseases but our results did not show consistent changes in all measured HIF-responsive proteins. Larger studies are needed to evaluate for additional genetic and environmental risk factors.