Plasma cell-derived mtDAMPs activate the macrophage STING pathway, promoting myeloma progression

Mitochondrial damage-associated molecular patterns (mtDAMPs) include proteins, lipids, metabolites, and DNA and have various context-specific immunoregulatory functions. Cell-free mitochondrial DNA (mtDNA) is recognized via pattern recognition receptors and is a potent activator of the innate immune system. Cell-free mtDNA is elevated in the circulation of trauma patients and patients with cancer; however, the functional consequences of elevated mtDNA are largely undefined. Multiple myeloma (MM) relies upon cellular interactions within the bone marrow (BM) microenvironment for survival and progression. Here, using in vivo models, we describe the role of MM cell-derived mtDAMPs in the protumoral BM microenvironment and the mechanism and functional consequence of mtDAMPs in myeloma disease progression. Initially, we identified elevated levels of mtDNA in the peripheral blood serum of patients with MM compared with those of healthy controls. Using the MM1S cells engrafted into nonobese diabetic severe combined immunodeficient gamma mice, we established that elevated mtDNA was derived from MM cells. We further show that BM macrophages sense and respond to mtDAMPs through the stimulator of interferon genes (STING) pathway, and inhibition of this pathway reduces MM tumor burden in the KaLwRij-5TGM1 mouse model. Moreover, we found that MM-derived mtDAMPs induced upregulation of chemokine signatures in BM macrophages, and inhibition of this signature resulted in egress of MM cells from the BM. Here, we demonstrate that malignant plasma cells release mtDNA, a form of mtDAMPs, into the myeloma BM microenvironment, which in turn activates macrophages via STING signaling. We establish the functional role of these mtDAMP-activated macrophages in promoting disease progression and retaining MM cells in the protumoral BM microenvironment.

LC3-associated phagocytosis in bone marrow macrophages suppresses acute myeloid leukemia progression through STING activation

The bone marrow (BM) microenvironment regulates acute myeloid leukemia (AML) initiation, proliferation, and chemotherapy resistance. Following cancer cell death, a growing body of evidence suggests an important role for remaining apoptotic debris in regulating the immunologic response to and growth of solid tumors. Here, we investigated the role of macrophage LC3–associated phagocytosis (LAP) within the BM microenvironment of AML. Depletion of BM macrophages (BMMs) increased AML growth in vivo. We show that LAP is the predominate method of BMM phagocytosis of dead and dying cells in the AML microenvironment. Targeted inhibition of LAP led to the accumulation of apoptotic cells (ACs) and apoptotic bodies (ABs), resulting in accelerated leukemia growth. Mechanistically, LAP of AML-derived ABs by BMMs resulted in stimulator of IFN genes (STING) pathway activation. We found that AML-derived mitochondrial damage–associated molecular patterns were processed by BMMs via LAP. Moreover, depletion of mitochondrial DNA (mtDNA) in AML-derived ABs showed that it was this mtDNA that was responsible for the induction of STING signaling in BMMs. Phenotypically, we found that STING activation suppressed AML growth through a mechanism related to increased phagocytosis. In summary, we report that macrophage LAP of apoptotic debris in the AML BM microenvironment suppressed tumor growth.

Abstract PO-141: The role of African Duffy-null allele related inflammation on the tumor microenvironment

DARC/ACKR1 erythrocyte expression, also known as the “Duffy blood group,” is understood to sequester pro-inflammatory chemokines and thereby regulate circulating gradients that direct immune cell infiltration. We hypothesize that this function also determines immune cell landscapes in the tumor microenvironment. Due to evolutionary selection pressures of malaria, individuals with sub-Saharan African ancestry typically carry the Duffy-null allele (rs4849887) and this lack of DARC/ACKR1 expression gives immunity to malaria while also allowing chronically high inflammation levels. Over 68% of African Americans (AA) have been found to have the Duffy-null genotype, compared to a rare 1-3% in European American individuals and we have shown it increases predisposition for Triple-Negative Breast Cancer (TNBC). In addition, we are currently studying if Duffy-null may contribute to higher breast cancer mortality that disproportionately affects AA women. This may be in part due to the role that low-DARC/ACKR1 expression plays in chronic inflammation, altering levels of several chemokines that modulate the migration and differentiation of specific immune cells. This role will impact tumor immune cell infiltration as well as the immune cell population composition overall, depending upon levels of DARC/ACKR1. Using RNA sequencing, our initial results indicated that for breast cancer tumors with high DARC/ACKR1 expression there was a higher estimated presence of CD8+ T cells, CD4+ T cells, regulatory T cells, follicular helper T cells, and memory B cells. Whereas with low DARC/ACKR1 expression, there was markedly less expression of resting dendritic cells and memory B cells. Therefore, in order to ascertain the influence DARC status has on spatial deposition and functional status of immune cell landscapes across the tumor microenvironment, we performed imaging mass cytometry on primary TNBC tumors. The panel contained tumor, structural, and immune markers, and was used to characterize the spatial differences between samples that had been verified to be DARC-high or DARC-low through immunohistochemistry. Our imaging analyses indicated that high DARC/ACKR1 expression correlates with infiltration of monocytes, macrophages, and cytotoxic T cells into the solid tumor microenvironment. Conversely, tumors with low DARC/ACKR1 expression showed monocytes and cytotoxic T cells contained in the tumor stroma. Using single-cell phenotyping, we were also able to identify distinct cell populations between DARC-high and -low. The tSNE analysis and heatmaps performed using Histology Topography Cytometry Analysis Toolbox (histoCAT), allowed us to visualize the spatial distribution of these cell populations, indicating an immune-suppressive tumor microenvironment in DARC-low tumors. These differences may be implicated in the causality of tumor progression as well as how to approach treatment given the cell heterogeneity of TNBC. This work provides greater context on the role that Duffy-null plays in chronic inflammation on the tumor microenvironment.

Citation Format: Yanira Guerra, Rachel Martini, Jessica Bensenhaver, Yalei Chen, Joseph K. Oppong, Ishmael Kyei, Frances S. Aitpillah, Michael O. Adinku, Joseph K. Oppong, Ernest K. Adjei, Aisha Jibril, Baffour Awuah, Mahteme Bekele, Engida Abebe, Kwasi Ankomah, Ernest B. Osei-Bonsu, Kofi K. Gyan, Clayton Yates, Kim Blenman, Olivier Elemento, Lisa Newman, Melissa B. Davis. The role of African Duffy-null allele related inflammation on the tumor microenvironment [abstract]. In: Proceedings of the AACR Virtual Conference: 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2021 Oct 6-8. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr PO-141.

Free fatty-acid transport via CD36 drives β-oxidation-mediated hematopoietic stem cell response to infection

Acute infection is known to induce rapid expansion of hematopoietic stem cells (HSCs), but the mechanisms supporting this expansion remain incomplete. Using mouse models, we show that inducible CD36 is required for free fatty acid uptake by HSCs during acute infection, allowing the metabolic transition from glycolysis towards β-oxidation. Mechanistically, high CD36 levels promote FFA uptake, which enables CPT1A to transport fatty acyl chains from the cytosol into the mitochondria. Without CD36-mediated FFA uptake, the HSCs are unable to enter the cell cycle, subsequently enhancing mortality in response to bacterial infection. These findings enhance our understanding of HSC metabolism in the bone marrow microenvironment, which supports the expansion of HSCs during pathogenic challenge.

Abstract 2799: Multiple myeloma derived mitochondrial DAMPs induce a pro-inflammatory signature in the bone marrow microenvironment to promote pro-tumoral expansion

Multiple myeloma (MM) is an incurable malignancy of antibody (Ig) secreting differentiated B cells (plasma cells) characterized by the accumulation and localization of tumor cells in the bone marrow microenvironment (BMM). Mitochondrial DNA (mtDNA) is a damage associated molecular pattern (DAMP), as the mitochondrial genome contains islands of unmethylated CpG nucleotide motifs that have been shown to activate and promote memory B cell proliferation and antibody secretion. Recent studies have indicated that mtDNA is elevated in the circulation of trauma and cancer patients. Here we investigate the functional purpose of elevated mtDNA within the BM microenvironment of MM.We hypothesize that multiple myeloma cells secrete mitochondrial DAMPs into the bone marrow microenvironment promoting a state of chronic inflammation that drives the progression and expansion of multiple myeloma. NSG immunocompromised mice engrafted with human MM1S myeloma cell line showed elevated levels of MM derived mtDNA in the serum, detected by real-time PCR. Next we engrafted C57BL/6 mice with murine 5TGM1 myeloma cell line to establish a syngeneic mouse model. Flow cytometry analysis of the haematopoietic stem and progenitor cell (HSPC) populations showed that 5TGM1 induced an inflammatory expansion of the stem cell niche To determine the role of mtDNA in HSPC expansion we treated C57BL/6 mice with multiple doses of CpG oligodeoxynucleotides to mimic mtDNA export by MM. Results showed similar expansion of haematopoietic stem and progenitor cell populations. To understand the effects of mtDAMPs on the inflammatory cells of the BMM, we show that bone marrow derived macrophages treated with mtDNA and CpG had increased expression of pro-inflammatory cytokines including IL-6. In vivo, isolated F4/80+ bone marrow macrophages from 5TGM1 and CpG treated mice also showed increased expression of pro-inflammatory cytokines. Finally, to understand the role of mtDAMPs in regulating HSPC expansion we used blocking antibodies to TLR9 (toll-like receptor 9 for mtDNA) and FPR1 (receptor for formylated mitochondrial proteins) in 5TGM1 engrafted animals. Blocking these receptors resulted in reduced myeloma tumor burden compared to control animals. Here we establish that MM releases mtDNA into the microenvironment and highlight the involvement of mtDAMPs in creating a pro-inflammatory BMM that aids in MM disease progression. This data suggests the potential for the targeting of TLR9 or FPR1 signaling pathways as a novel therapeutic approach for MM.

Citation Format: Aisha Jibril, Prakrit Kumar, Charlotte Hellmich, Jamie A. Moore, Jayna J. Mistry, Victoria Willimott, Kristian M. Bowles, Stuart A. Rushworth. Multiple myeloma derived mitochondrial DAMPs induce a pro-inflammatory signature in the bone marrow microenvironment to promote pro-tumoral expansion [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2799.

Abstract 2752: LC3-associated phagocytosis in bone marrow macrophages suppresses AML progression through TIM-4 mediated STING activation

Acute myeloid leukemia (AML) is a tumor dependent on its interactions within the bone marrow (BM) microenvironment. LC3-associated phagocytosis (LAP) maintains tissue homeostasis by regulating immune responses, including in tumor immunity. Here we investigate the function of LAP in the AML BM microenvironment.

We used two syngeneic leukemia models (HOXA9/Meis1 and MN1)to investigate the role of LAP on AML proliferation. AML cells were injected into LAP deficient (LAP-/-; ATG16E230-/-) and wild-type (WT) mice. LAP-/- mice had increased AML engraftment in the BM compared to WT mice, as well as reduced animal survival. Flow cytometry (Annexin+) of the BM microenvironment showed an increase in apoptosis in the BM compartment of mice engrafted with AML. This was further increased in LAP-/- mice with AML.

The number of BM macrophages (MØ) (CD45+, GR1-, F4/80+ CD115INT) did not differ between the WT and LAP-/- mice. Next, we quantified MØ numbers in the BM of WT and LAP-/- mice with AML. We found increased numbers of tumor associated CD206+ BM MØ in LAP-/- mice with AML compared to WT animals with AML. Gene expression analysis showed up-regulation of type I interferons (IFNs) relating to the STING pathway in the WT engrafted mice. Inhibition of the STING pathway reversed the LAP dependent AML suppression of inflammatory cytokines, suggesting LAP processing of apoptotic cells is important for STING activation.

AML has high mtDNA content compared to non-malignant cells, and as mtDNA can activate the STING pathway via cGAS we studied the effects of AML cells without mtDNA (AML ρ0) on STING pathway activation. Induction of apoptosis in AML ρ0 cells followed by co-culture with BM derived MØ (BMDM) for 24 hours did not activate the STING pathway in the MØ. In contrast, MØ co-culture with mitochondria containing apoptotic AML cells did activate the MØ STING pathway.

STING pathway activation via type I IFNs induces recruitment of cytotoxic T cells, but no increase in CD8+ T cell numbers or activation (Granzyme-B and IFN-γ) was observed in the BM between LAP-/- and WT animals engrafted with AML. Type I IFNs produced by MØ have been shown to act in an autocrine manner, we therefore investigated MØ phagocytic capacity in AML. Ex-vivo analysis showed enhanced phagocytosis and LAP processing of Zymosan fluorescent beads and LC3 association in MØ from AML engrafted mice compared to controls. Engulfment of apoptotic cells by MØ requires recognition of phosphatidylserine by surface TIM-4 which mediates LAP. We found TIM-4 inhibition increased AML proliferation in vivo. Finally, ex vivo analysis of TIM-4 inhibited MØ confirmed reduced LAP.

We report that BM MØ process apoptotic AML cells via LAP through TIM-4. Furthermore, AML apoptotic bodies containing mtDNA initiate MØ STING activation and inhibit AML proliferation.

Citation Format: Jamie Aaron Moore, Jayna J. Mistry, Charlotte Hellmich, Aisha Jibril, Tom Wileman, Angela Collins, Kristian M. Bowles, Stuart A. Rushworth. LC3-associated phagocytosis in bone marrow macrophages suppresses AML progression through TIM-4 mediated STING activation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2752.

Abstract 1048: Targeting BCL-2 and CD38 in models of acute myeloid leukemia reduces tumour burden

The prognosis for patients with acute myeloid leukemia (AML) remains poor with high mortality rates. It is often not possible to achieve complete remission with current therapy and relapse following treatment is common. New and more targeted treatment approaches are therefore needed to improve outcomes for patients. AML progression and treatment resistance has been associated with overexpression of BCL2. Venetoclax, a BH3 mimetic targeting BCL2, has been shown to effectively target AML cells and induce cell death. It has been approved for the treatment of AML but as with other AML treatments not all patients respond, and others develop treatment resistance. Research has therefore focussed on exploring combination therapies for Venetoclax. Our group has previously shown that mitochondrial transfer from mesenchymal stromal cells (MSC) to AML blasts promotes AML growth and is mediated by CD38. Daratumumab targets CD38 and inhibits this transfer, which results in impaired AML growth and improved animal survival. Here, we investigate the effect of inhibiting both CD38 with daratumumab and BCL2 with Venetoclax on the survival of AML. Primary AML blasts and MSC were isolated from patients' bone marrow in accordance with the Declaration of Helsinki. Flow cytometry was used to measure CD38 and BCL2 expression in AML blasts compared to normal CD34+ progenitor cells. BCL2 expression was significantly higher in AML blasts and CD38 expression was also increased. Cell viability was significantly reduced following treatment with Venetoclax alone, whilst Daratumumab alone or in combination with Venetoclax did not affect AML survival further. However, the action of daratumumab relies on the bone marrow microenvironment and AML blasts were therefore co-cultured with MSC and then treated with Venetoclax or daratumumab or in combination. After 24 hours cells were stained with Annexin V-FITC/PI and flow cytometry was used to assess levels of apoptosis. Combination treatment with Venetoclax and Daratumumab resulted in significantly more apoptosis in AML cells compared to AML cells treated with single agent. Finally, the effect of combination treatment with Venetoclax and Daratumumab was assessed in vivo using an NSG xenograft mouse model of AML. Mice were engrafted with MV411-luc or patient derived AML and then treated with vehicle control (PBS) or daratumumab alone (5mg/kg on day 7 and 14) or Venetoclax alone (100mg/kg/day) or both daratumumab and Venetoclax. Bioluminescence imaging was used to assess disease engraftment and progression before and after treatment. Combining treatment with Daratumumab and Venetoclax in vivo significantly reduced tumour burden and improved animal survival compared to control or single agent.

This data supports that combination treatment with Venetoclax and Daratumumab could have an important clinical application in the treatment of AML.

Citation Format: Charlotte Hellmich, Jayna J. Mistry, Amelia Lambert, Jamie A. Moore, Aisha Jibril, Angela Collins, Kristian M. Bowles, Stuart A. Rushworth. Targeting BCL-2 and CD38 in models of acute myeloid leukemia reduces tumour burden [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1048.

Venetoclax and Daratumumab combination treatment demonstrates pre-clinical efficacy in mouse models of Acute Myeloid Leukemia

Acute myeloid leukemia (AML) remains an incurable malignancy despite recent advances in treatment. Recently a number of new therapies have emerged for the treatment of AML which target BCL-2 or the membrane receptor CD38. Here, we show that treatment with Venetoclax and Daratumumab combination resulted in a slower tumor progression and a reduced leukemia growth both in vitro and in vivo. These data provide evidence for clinical evaluation of Venetoclax and Daratumumab combination in the treatment of AML.

Investigation of triple-negative breast cancer risk alleles in an International African-enriched cohort

Large-scale efforts to identify breast cancer (BC) risk alleles have historically taken place among women of European ancestry. Recently, there are new efforts to verify if these alleles increase risk in African American (AA) women as well. We investigated the effect of previously reported AA breast cancer and triple-negative breast cancer (TNBC) risk alleles in our African-enriched International Center for the Study of Breast Cancer Subtypes (ICSBCS) cohort. Using case-control, case-series and race-nested approaches, we report that the Duffy-null allele (rs2814778) is associated with TNBC risk (OR = 3.814, p = 0.001), specifically among AA individuals, after adjusting for self-indicated race and west African ancestry (OR = 3.368, p = 0.007). We have also validated the protective effect of the minor allele of the ANKLE1 missense variant rs2363956 among AA for TNBC (OR = 0.420, p = 0.005). Our results suggest that an ancestry-specific Duffy-null allele and differential prevalence of a polymorphic gene variant of ANKLE1 may play a role in TNBC breast cancer outcomes. These findings present opportunities for therapeutic potential and future studies to address race-specific differences in TNBC risk and disease outcome.

Abstract 2643: ROS dependent PGC1alpha driven mitochondrial biogenesis within the melanoma microenvironment is a pre-requisite for mitochondrial transfer from MSC to malignant cells

The tumor microenvironment is essential for the growth and proliferation of melanoma. Recently, reports have shown that mitochondria are transferred from mesenchymal stromal cells (MSCs) to melanoma tumor cells through tunneling nanotubes (TNTs), a process which supports their proliferation in-vitro and in-vivo. Moreover, we have shown in leukemia that tumor superoxide provides the stimulus to drive mitochondrial transfer in this way. In the present study we specifically examine the effects of melanoma cells on MSC mitochondrial biogenesis and subsequent mitochondrial transfer to the malignant cell. Primary melanoma cells, and MSCs derived from the bone marrow of patients without melanoma were obtained after informed consent and under approval from the UK Health Research Authority, and in accordance with the Declaration of Helsinki. Primary cells were characterized using flow cytometry. Genes involved in mitochondria biogenesis, fission/fusion and activity were analysed using Real-time PCR and Western blotting. Mitochondrial transfer was assessed and quantified in-vitro using a MitoTracker green FM staining and flow cytometry. Melanoma signals were quenched by various inhibitors including glutathione and diphenyleneiodonium (DPI). Melanoma proliferation and tumor volume, in an NSG xenograft subcutaneous model, were monitored through bioluminescent live animal imaging. First, we confirmed primary melanoma cell identity using CD45-, CD31-, CD166+ and CD146+ staining using flow cytometry. Next, we quantified levels of mitochondrial transfer from MSC to melanoma, with and without inhibition of superoxide activity. We found that the anti-oxidants glutathione and DPI significantly reduced levels of mitochondrial transfer from MSCs to melanoma. We next quantified mitochondrial biogenesis within MSCs, showing that MSCs had increased mitochondrial DNA and increased MitoTracker green FM staining in response to co-culture with melanoma. Next, we found that this increase in mitochondrial content also occurred in response to hydrogen peroxide, which mimics the effects of melanoma-derived ROS. In addition, we show that PGC1α (master regulator of mitochondrial biogenesis) levels in the nucleus of MSCs increased when cultured with melanoma. Moreover, knockdown of PGC1α inhibited mitochondrial biogenesis in MSCs when cultured with melanoma or activated with hydrogen peroxide. Furthermore, transfer of mitochondria from MSCs to melanoma was substantially reduced when MSC-derived PGC1α was silenced. Finally, we engrafted control or PGC1α knockdown MSCs together with melanoma cell lines into the sub-cutaneous tissue of NSG mice. We found significantly reduced tumor volume when the melanoma was transplanted with the PGC1α knockdown MSCs compared to transplant of melanoma with the control knockdown MSC. Here we report that the ROS generated by melanoma cells drives MSC mitochondrial biogenesis and subsequent mitochondrial transfer from MSCs to melanoma cells. Targeting this pathway may provide an effective novel therapeutic approach in melanoma.

Citation Format: Prakrit Kumar, Jayna Mistry, Jamie Moore, Charlotte Hellmich, Aisha Jibril, Christopher Morris, Marc Moncrieff, Kristian Bowles, Stuart Rushworth. ROS dependent PGC1alpha driven mitochondrial biogenesis within the melanoma microenvironment is a pre-requisite for mitochondrial transfer from MSC to malignant cells [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2643.

Parents' perceptions of core outcomes in neonatal research in two Nigerian neonatal units

BACKGROUND

There is a scarcity of information regarding the most important outcomes for research in neonatal units in low-resource settings. Identification of important outcomes by different stakeholder groups would inform the development of a core outcome set (COS) for use in neonatal research.

OBJECTIVE

To determine the perceptions and opinions of parents of newborn babies regarding what outcomes were most important to them in order to contribute towards development of a COS for neonatal research in sub-Saharan Africa.

METHODS

Semistructured interviews were undertaken with parents, mostly mothers, of babies admitted to one neonatal unit in North central and one in Southwest Nigeria. Participants were purposively sampled to include parents of babies with common neonatal problems such as prematurity.

RESULTS

We conducted 31 interviews. The most frequently raised outcomes were breast feeding, good health outcomes for their baby, education, growth and financial cost. Parents placed more emphasis on quality of life and functional status than health complications.

CONCLUSIONS

The opinions of parents need to be considered in developing a COS for neonatal research in low-resource settings. Further research should assess the opinions of families in other low-resource settings and also engage a broader range of stakeholders.

Beyond triple-negative breast cancer and African ancestry: Tumor phenotypes among internationally diverse patient populations

1101

Background: Population-based incidence rates of breast cancers that are negative for estrogen receptor (ER), progesterone receptor (PR), and HER2/ neu(triple negative breast cancer {TNBC}) are higher among African American (AA) compared to White American (WA) women. Several studies show higher TNBC frequency among selected populations of African patients. The colonial-era trans-Atlantic slave trade resulted in shared West African ancestry between contemporary AA and Ghanaian (Gh) populations. The extent to which TNBC susceptibility is related to East African versus West African ancestry, and whether these associations extend to expression of other biomarkers such as Androgen Receptor (AR) and mammary stem cell marker ALDH1 is unknown. Methods: We used immunohistochemistry to assess ER, PR, HER2/ neu, AR and ALDH1 among WA (n = 153); AA (n = 76); Ethiopian (Eth)/East African (n = 90) and (Gh)/West African (n = 286) breast cancers through an IRB-approved international research program. Results: Mean age at breast cancer diagnosis was 43; 49; 60; and 57 years for the Eth; Gh; AA; and WA patients, respectively. Frequency of TNBC was significantly higher for AA and Gh patients (54% and 41%, respectively) compared to WA and Eth patients (23% and 15%, respectively); p < 0.001. These associations were unchanged when limited to patients age 50 and younger (47% and 49% for AA and Gh, respectively; versus 18% and 16% for WA and Eth, respectively); p < 0.001. Frequency of ALDH1 positivity was also higher for tumors from AA and Gh patients (32% and 36%, respectively) compared to those from WA and Eth patients (23% and 17%, respectively); p = 0.007. Significant differences were observed for distribution of AR positivity, which was 71%; 55%; 42% and 50% for the WA; AA; Gh; and Eth cases, respectively (p = 0.008). Conclusions: We found a correlation between extent of African ancestry and risk of particular BC phenotypes. West African ancestry was associated with increased risk of TNBC and breast cancers that are positive for ALDH1. Future studies of hereditary TNBC susceptibility among women with African ancestry are warranted.

Laparoscopic management of a large ovarian cyst in the neonate

Laparotomy has become the preferred approach to the excision of large, complex abdominal cysts in the neonate. We describe a laparoscopic-assisted decapsulation of an antenatally diagnosed abdominal cyst that was noted on postnatal ultrasound scan to have a complex echo pattern. This limited procedure allows for accurate verification of the diagnosis, institution of appropriate therapy, and organ salvage. It represents a superior management option that obviates the significant complications associated with conservative management.

[Late potentials in chronic alcoholics]

OBJECTIVE

Cardiac arrest is the most frequent cause of death in chronic alcoholics. Detection of late potentials in this population could be helpful in screening from early signs of myocardial disorders and identifying patients at risk of severe ventricular dysrythmia.

PATIENTS AND METHODS

A prospective study of late potentials was conducted in 53 subjects (mean age 49 +/- 10 years) with a history of long-standing alcohol abuse (mean 13.6 +/- 8.5 years, mean daily alcohol intake 86 +/- 30 g). After a period of abstinence, the following explorations were performed: liver tests, liver biopsy, electrocardiogram, echocardiography, Holter recording.

RESULTS

Among the 53 patients, 37% were positive for 2 of the 3 criteria for late potentials. There was a strong correlation between the duration of alcohol abuse and presence of late potentials (p = 0.006, r = 0.37). The percentage of hepatic steatosis was higher in alcoholic subjects with late potentials (34% versus 23%; p = 0.05) and was correlated with the number of positive criteria for late potentials (p = 0.05, r = 0.328). Finally, the presence of late potentials was also correlated with the following laboratory results: serum gamma glutamyltranspeptidase (p = 0.031), serum aspartate amino transferase (p = 0.033), serum alkaline phosphatases (p = 0.0025).

CONCLUSION

Late potentials can be detected easily although their prognostic value remains to be determined. They could be an early marker of infraclinical myocardial lesions.

[Signal averaging electrocardiography in chronic alcoholism]

Cardiovascular death is the main cause of mortality in chronic alcoholics, perhaps due to a pro-arrhythmogenic effect of alcohol associated with infraclinical myocardial lesions. The authors investigated prospectively 41 patients (average age: 49.7 years) who were chronic alcoholics but had no acute alcoholic episodes for cardiac disease (ECG, signal averaging for late ventricular potentials, echocardiography and Holter ECG monitoring) and hepatic disease (liver biopsy). The history of alcoholism was 14 +/- 9 years, the quantity of alcohol ingested before they stopped drinking being 89 +/- 31 grammes/day. Thirty per cent of patients displayed 2 or 3 criteria of late ventricular potentials (LP). The authors demonstrated a correlation between the daily quantity of alcohol consumed before stopping drinking and the duration of the filtered QRS complex (p = 0.02). Moreover, the frequency of fatty infiltration found on liver biopsy, greater in alcoholics with LP (35% versus 19%, p = 0.025) correlated with the amplitude of the last 40 ms of the average QRS (p = 0.0485), with the duration of potentials of less than 40 microvolts (p = 0.05) and, above all, with the number of criteria of LP (p = 0.02). Finally, the presence of LP was also related to the following biological abnormalities: GGT (p = 0.027), ASAT (p = 0.046), ALAT (p = 0.039). The ECG abnormalities may reflect early infra-clinical myocardial lesions secondary to cellular metabolic abnormalities perhaps analogous to the fatty hepatic changes. However, the prognostic value of these signal-averaging ECG abnormalities remains unknown.