Panagiotis Theodorou Diamantopoulos

Dr. Panagiotis Theodorou Diamantopoulos

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Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

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

Representative Publications

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3 January 2012 in Virology Journal
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PDPanagiotis Theodorou Diamantopoulos
Panagiotis Theodorou Diamantopoulos
MMMaria Michael
Maria Michael
OBOlga Benopoulou
Olga Benopoulou
EBEfthymia Bazanis
Efthymia Bazanis
GTGeorge Tzeletas
George Tzeletas
NVNora-Athina Viniou
Nora-Athina Viniou
Myelodysplastic syndromes (MDS) are often accompanied by autoimmune phenomena. The underlying mechanisms for these associations remain uncertain, although T cell activation seems to be important. Human T-lymphotropic virus (HTLV-1) has been detected in patients with myelodysplastic syndromes, mostly in regions of the world which are endemic for the virus, and where association of HTLV-1 with rheumatological manifestation is not rare. We present here the case of a 58 year old man who presented with cytopenias, leukocytoclastic vasculitis of the skin and glomerulopathy, and was diagnosed as MDS (refractory anemia with excess blasts - RAEB 1). The patient also tested positive for HTLV-1 by PCR. After 8 monthly cycles of 5-azacytidine he achieved a complete hematologic remission. Following treatment, a second PCR for HTLV-1 was carried out and found to be negative. This is the first report in the literature of a HTLV-1-positive MDS with severe autoimmune manifestations, which was treated with the hypomethylating factor 5-azacitidine, achieving cytogenetic remission with concomitant resolution of the autoimmune manifestations, as well as HTLV-1-PCR negativity. HTLV-1-PCR negativity may be due to either immune mediated clearance of the virus, or a potential antiretroviral effect of 5-azacytidine. 5-azacytidine is known for its antiretroviral effects, although there is no proof of its activity against HTLV-1 infection in vivo.

13 September 2019 in Cancer Medicine
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EKEva Kassi
Eva Kassi
AAAnna Angelousi
Anna Angelousi
NANikolaos Asonitis
Nikolaos Asonitis
PDPanagiotis Theodorou Diamantopoulos
Panagiotis Theodorou Diamantopoulos
AAAmalia Anastasopoulou
Amalia Anastasopoulou
HGHelen Gogas
Helen Gogas
Background: Immune‐checkpoint inhibitors have been shown to improve survival in melanoma patients, but can also trigger immune‐related endocrinopathies, especially hypophysitis and thyroid dysfunction.Methods: To assess the incidence and the spectrum of endocrinopathies in melanoma patients treated with immunotherapy a prospective observational study was conducted. Forty out of 339 patients, treated with immune‐checkpoint inhibitors, developed endocrinopathies. All patients had hormonal functional tests at screening (before the initiation of immunotherapy) and during follow‐up.Results: The total incidence of endocrinopathies was 11.8%, 13.4% due to anti‐PD1/PDL1, 5% due to anti‐CTLA4, and 18.5% due to sequential and/or combination treatment. Twenty‐one patients (6.2%) presented with isolated anterior hypophysitis, eleven (3.2%) with primary thyroid dysfunction and eight (2.4%) with both abnormalities. The most frequent anterior pituitary hormone deficiency was central adrenal insufficiency, followed by central hypothyroidism and hypogonadotrophic hypogonadism. None of the patients with corticotroph axis failure recovered during follow‐up. Endocrinopathies occurred after a median of 22 weeks (range: 4‐156) from treatment initiation. Of note, sequential and/or combination therapy with anti‐CTLA4 and anti‐PD1/anti‐PDL1 led to an almost threefold incidence of hypophysitis compared to either monotherapy. Only one of 120 patients receiving anti‐CTLA4 monotherapy developed primary hypothyroidism.Conclusions: Our cohort demonstrated an increased incidence of hypophysitis with anti‐PD1/anti‐PDL1 in contrast to the rarity of primary thyroid dysfunction with anti‐CTLA4 treatment. These results could be attributed to genetic/ethnic differences. Sequential treatment is, for the first time to our knowledge, reported to increase the risk of developing hypophysitis to a level as high as that of combination therapy.

23 November 2021 in Blood Advances
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CKChristina-Nefeli Kontandreopoulou
Christina-Nefeli Kontandreopoulou
PDPanagiotis Theodorou Diamantopoulos
Panagiotis Theodorou Diamantopoulos
DTDespina Tiblalexi
Despina Tiblalexi
NGNefeli Giannakopoulou
Nefeli Giannakopoulou
NVNora-Athina Viniou
Nora-Athina Viniou
Poly(ADP-ribose) polymerase 1 (PARP1) is a key mediator of various forms of DNA damage repair and plays an important role in the progression of several cancer types. The enzyme is activated by binding to DNA single-strand and double-strand breaks. Its contribution to chromatin remodeling makes PARP1 crucial for gene expression regulation. Inhibition of its activity with small molecules leads to the synthetic lethal effect by impeding DNA repair in the treatment of cancer cells. At first, PARP1 inhibitors (PARPis) were developed to target breast cancer mutated cancer cells. Currently, PARPis are being studied to be used in a broader variety of patients either as single agents or in combination with chemotherapy, antiangiogenic agents, ionizing radiation, and immune checkpoint inhibitors. Ongoing clinical trials on olaparib, rucaparib, niraparib, veliparib, and the recent talazoparib show the advantage of these agents in overcoming PARPi resistance and underline their efficacy in targeted treatment of several hematologic malignancies. In this review, focusing on the crucial role of PARP1 in physiological and pathological effects in myelodysplastic syndrome and acute myeloid leukemia, we give an outline of the enzyme’s mechanisms of action and its role in the pathophysiology and prognosis of myelodysplastic syndrome/acute myeloid leukemia and we analyze the available data on the use of PARPis, highlighting their promising advances in clinical application.

3 August 2014 in BioMed Research International
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PDPanagiotis Theodorou Diamantopoulos
Panagiotis Theodorou Diamantopoulos
MSMaria Sofotasiou
Maria Sofotasiou
VPVasiliki Papadopoulou
Vasiliki Papadopoulou
KPKaterina Polonyfi
Katerina Polonyfi
TITheodoros Iliakis
Theodoros Iliakis
NVNora-Athina Viniou
Nora-Athina Viniou
Chronic lymphocytic leukemia (CLL) is considered a malignancy resulting from defects in apoptosis. For this reason, targeting apoptotic pathways in CLL may be valuable for its management. Poly [ADP-ribose] polymerase 1 (PARP1) is the main member of a family of nuclear enzymes that act as DNA damage sensors. Through binding on DNA damaged structures, PARP1 recruits repair enzymes and serves as a survival factor, but if the damage is severe enough, its action may lead the cell to apoptosis through caspase activation, or necrosis. We measured thePARP1mRNA and protein pretreatment levels in 26 patients with CLL and the corresponding posttreatment levels in 15 patients after 3 cycles of immunochemotherapy, as well as in 15 healthy blood donors. No difference was found between the pre- and posttreatment levels of PARP1, but we found a statistically significant relative increase of the 89 kDa fragment of PARP1 that is cleaved by caspases in the posttreatment samples, indicating PARP1-related apoptosis in CLL patients after treatment. Our findings constitute an important step in the field, especially in the era of PARP1 inhibitors, and may serve as a base for future clinical trials with these agents in CLL.

18 May 2012 in Hematological Oncology
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SPSotirios Papageorgiou
Sotirios Papageorgiou
PDPanagiotis Theodorou Diamantopoulos
Panagiotis Theodorou Diamantopoulos
GLGeorgia Levidou
Georgia Levidou
MAMaria K. Angelopoulou
Maria K. Angelopoulou
PEPanagiota Economopoulou
Panagiota Economopoulou
Theodoros VassilakopoulosTheodoros Vassilakopoulos
Theodoros Vassilakopoulos
Central nervous system (CNS) involvement in patients with primary mediastinal large B‐cell (PMLBCL) lymphoma is a rare event, occurring in approximately 6% of patients, on the basis of the review of the literature prior to induction of Rituximab. The aim of this retrospective study was to describe the incidence of CNS relapse among 100 consecutive patients with PMLBCL who were treated with R‐CHOP ± RT in comparison to patients treated with CHOP ± RT (n = 45) in 11 hospitals in Greece. Two patients experienced a CNS relapse, representing an overall frequency of 2.0% in R‐CHOP treated patients and a 2‐year actuarial incidence of 2.3%. Both patients had isolated CNS relapses. The incidence of CNS relapse after CHOP without Rituximab was 2/45 (4.4%) for a 2‐year actuarial incidence of 7.5% (p = 0.29). Again, both patients had isolated CNS relapses. Parenchymal‐only localizations accounted for 3/4 cases. Risk factors for CNS involvement could include leukocytosis, poor performance status and higher age‐adjusted International Prognostic Index, although their impact was weakened by competing risk survival analysis. Both patients relapsing after R‐CHOP required CNS radiotherapy to achieve a complete remission and be forwarded to high‐dose therapy and autologous stem cell transplantation: They are both alive and disease‐free 18 and 23 months after CNS relapse. Both cases relapsing after CHOP without Rituximab were salvaged by CNS radiotherapy (one also received intrathecal chemotherapy) entering long‐term remissions. In conclusion, CNS relapses are rare in PMLBCL tending to be isolated in the CNS, probably reflecting the persistence of latent CNS disease than dissemination of resistant disease. The impact of Rituximab in reducing CNS relapses remains unknown. Established risk factors for CNS involvement in aggressive lymphomas may not be helpful in assessing the risk of CNS recurrence in this disease. Routine CNS prophylaxis is not probably required in PMLBCL. Copyright © 2012 John Wiley & Sons, Ltd.

26 February 2019 in Cancer Immunology, Immunotherapy
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BSBastian Schilling
Bastian Schilling
AMAlexander Martens
Alexander Martens
MFMarnix H. Geukes Foppen
Marnix H. Geukes Foppen
Christoffer GebhardtChristoffer Gebhardt
Christoffer Gebhardt
JHJessica C. Hassel
Jessica C. Hassel
BWBenjamin Weide
Benjamin Weide