Naser Elkum

Dr. Naser Elkum


Research Focus & Metrics

Academic Career Length

26Years (2001-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 March 2006 in Neoplasia
Verified
Journal Article
Open access
Hazem GhebehHazem Ghebeh
Hazem Ghebeh
SMShamayel Mohammed
Shamayel Mohammed
AAAbeer Al-Omair
Abeer Al-Omair
AQAmal Qattant
Amal Qattant
CLCynthia Lehe
Cynthia Lehe
Said DermimeSaid Dermime
Said Dermime
B7-H1 molecule increases the apoptosis of tumor-reactive T lymphocytes and reduces their immunogenicity. Breast cancer is the second most common cause of mortality after lung cancer. Direct evidence linking B7-H1 with cancer has been shown in several malignancies; however, its expression in breast cancer has not been investigated. We used immunohistochemistry to investigate the expression of the B7-H1 molecule in 44 breast cancer specimens and to study its correlation with patients' clinicopathological parameters. The expression of B7-H1 was shown in 22 of 44 patients and was not restricted to the tumor epithelium (15 of 44, 34% in tumor cells), but was also expressed by tumor-infiltrating lymphocytes (TIL; 18 of 44, 41%). Interestingly, intratumor expression of B7-H1 was significantly associated with histologic grade III-negative (P = .012), estrogen receptor-negative (P = .036), and progesterone receptor-negative (P = .040) patients. In addition, the expression of B7-H1 in TIL was associated with large tumor size (P = .042), histologic grade III (P = .015), positivity of Her2/neu status (P = .019), and severe tumor lymphocyte infiltration (P = .001). Taken together, these data suggest that B7-H1 may be an important risk factor in breast cancer patients and may represent a potential immunotherapeutic target using monoclonal antibody against the B7-H1 molecule.

23 February 2008 in BMC Cancer
Verified
Journal Article
Open access
PDF file
Hazem GhebehHazem Ghebeh
Hazem Ghebeh
EBEman Barhoush
Eman Barhoush
ATAsma Tulbah
Asma Tulbah
NENaser Elkum
Naser Elkum
TATaher AL-Tweigeri
Taher AL-Tweigeri
Said DermimeSaid Dermime
Said Dermime
Background: Recent studies have demonstrated a direct involvement of B7-H1, PD-1 and FOXP3 molecules in the immune escape of cancer. B7-H1 is an inhibitory molecule that binds to PD-1 on T lymphocytes, while FOXP3 is a marker for regulatory T cells (Tregs). We have previously demonstrated the association of B7-H1-expressing T infiltrating lymphocytes (TIL) with high-risk breast cancer patients while other studies reported the involvement of FOXP3+ Tregsas a bad prognostic factor in breast tumors. Although the co-existence between the two types of cells has been demonstratedin vitroand animal models, their relative infiltration and correlation with the clinicopathological parameters of cancer patients have not been well studied. Therefore, we investigated TIL-expressing the B7-H1, PD-1, and FOXP3 molecules, in the microenvironment of human breast tumors and their possible association with the progression of the disease.Methods: Using immunohistochemistry, tumor sections from 62 breast cancer patients were co-stained for B7-H1, PD-1 and FOXP3 molecules and their expression was statistically correlated with factors known to be involved in the progression of the disease.Results: A co-existence of B7-H1+T lymphocytes and FOXP3+Tregswas evidenced by the highly significant correlation of these molecules (P< .0001) and their expression by different T lymphocyte subsets was clearly demonstrated. Interestingly, concomitant presence of FOXP3+Tregs, B7-H1+and PD-1+TIL synergistically correlated with high histological grade (III) (P< .001), estrogen receptor negative status (P= .017), and the presence of severe lymphocytic infiltration (P= .022).Conclusion: Accumulation of TIL-expressing such inhibitory molecules may deteriorate the immunity of high-risk breast cancer patients and this should encourage vigorous combinatorial immunotherapeutic approaches targeting Tregsand B7-H1/PD-1 molecules.

5 April 2007 in International Journal of Cancer
Verified
Journal Article
Closed access
PDF file
Hazem GhebehHazem Ghebeh
Hazem Ghebeh
ATAsma Tulbah
Asma Tulbah
SMShamayel Mohammed
Shamayel Mohammed
NENaser Elkum
Naser Elkum
SASuad M. Bin Amer
Suad M. Bin Amer
Said DermimeSaid Dermime
Said Dermime

16 June 2015 in Scientific Reports
Verified
Journal Article
Open access
PDF file
Mohamed Abu-farhaMohamed Abu-farha
Mohamed Abu-farha
JAJehad Abubaker
Jehad Abubaker
IAIrina Al-Khairi
Irina Al-Khairi
PCPreethi Cherian
Preethi Cherian
FNFiona Noronha
Fiona Noronha
NENaser Elkum
Naser Elkum
Betatrophin/ANGPTL8 is a newly identified hormone produced in liver and adipose tissue that has been shown to be induced as a result of insulin resistance and regulates lipid metabolism. Little is known about betatrophin level in humans and its association with T2D and metabolic risk factors. Plasma level of betatrophin was measured by ELISA in 1603 subjects: 1047 non-diabetic and 556 T2D subjects and its associations with metabolic risk factors in both non-diabetic and T2D were also studied. Our data show a significant difference in betatrophin levels between non-diabetic (731.3 (59.5–10625.0) pg/ml) and T2D (1710.5 (197.4–12361.1) p < 0.001. Betatrophin was positively correlated with age, BMI, waist/hip ratio, FBG, HbA1C, HOMA-IR and TG in the non-diabetic subjects. However, no association was observed with BMI, FBG, HbA1C or HOMA-IR in T2D subjects. TC and LDL showed negative association with betatrophin in T2D subjects. Multivariate analysis showed that subjects in the highest tertile of betatrophin had higher odds of having T2D (odd ratio [OR] = 6.15, 95% confidence interval [CI] = (3.15 – 12.01). Our data show strong positive associations between betatrophin and FBG and insulin resistance in non-diabetic subjects. However, correlations with FBG and insulin resistance were diminished in T2D subjects.

26 January 2006 in Leukemia
Verified
Journal Article
Closed access
TOTarek Owaidah
Tarek Owaidah
ABA Al Beihany
A Al Beihany
MIM A Iqbal
M A Iqbal
NENaser Elkum
Naser Elkum
GRG T Roberts
G T Roberts

19 January 2016 in PLOS ONE
Verified
Journal Article
Open access
PDF file
Mohamed Abu-farhaMohamed Abu-farha
Mohamed Abu-farha
DSDevarajan Sriraman
Devarajan Sriraman
PCPreethi Cherian
Preethi Cherian
IAIrina AlKhairi
Irina AlKhairi
NENaser Elkum
Naser Elkum
JAJehad Abubaker
Jehad Abubaker
ANGPTL8 is a liver and adipose tissue produced protein that regulates the level of triglyceride in plasma as well as glucose homeostasis. This study was designed to evaluate the level of ANGPTL8 in obese and non-obese subjects before and after exercise training. A total of 82 non-obese and 62 adult obese were enrolled in this study. Subjects underwent a three months of exercise training. Both full length and C-terminal 139–198 form of ANGPTL8 were measured by ELISA. Our data show that the full length ANGPTL8 level was increased in obese subjects (1150.04 ± 108.10 pg/mL) compared to non-obese (775.54 ± 46.12) pg/mL (p-Value = 0.002). C-terminal 139–198 form of ANGPTL8 was also increased in obese subjects 0.28 ± 0.04 ng/mL vs 0.20 ± 0.02 ng/mL in non-obese (p-value = 0.058). In obese subjects, the levels of both forms were reduced after three months of exercise training; full length was reduced from 1150.04 ± 108.10 pg/mL to 852.04 ± 51.95 pg/mL (p-Values 0.015) and c-terminal form was reduced from 0.28 ± 0.04 ng/mL to 0.19 ± 0.03 ng/mL (p-Value = 0.058). Interestingly, full length ANGPTL8 was positively associated with fasting blood glucose (FBG) in non-obese (r = 0.317, p-Value = 0.006) and obese subjects (r = 0.346, p-Value = 0.006) C-terminal 139–198 form of ANGPTL8 on the other hand, did not show any correlation in both groups. In conclusion, our data demonstrate that ANGPTL8 was increased in obesity and reduced after exercise training supporting the potential therapeutic benefit of reducing ANGPTL8. The various forms of ANGPTL8 associated differently with FBG suggesting that they have different roles in glucose homeostasis.