Dace Pjanova

Dr. Dace Pjanova

Latvian Biomedical Research and Study Centre, Riga, Rīga, Latvia
orcid

Research Focus & Metrics

Academic Career Length

24Years (2003-Present)

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

Representative Publications

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5 February 2013 in Journal of Medical Genetics
Verified
Journal Article
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HPHanne Eknes Puntervoll
Hanne Eknes Puntervoll
XYXiaohong R Yang
Xiaohong R Yang
HVHildegunn Høberg Vetti
Hildegunn Høberg Vetti
IBIngeborg M Bachmann
Ingeborg M Bachmann
MAMarie Françoise Avril
Marie Françoise Avril
AMAnders Molven
Anders Molven
Background CDKN2A and CDK4 are high risk susceptibility genes for cutaneous malignant melanoma. Melanoma families with CDKN2A germline mutations have been extensively characterised, whereas CDK4 families are rare and lack a systematic investigation of their phenotype. Methods All known families with CDK4 germline mutations (n=17) were recruited for the study by contacting the authors of published papers or by requests via the Melanoma Genetics Consortium (GenoMEL). Phenotypic data related to primary melanoma and pigmentation characteristics were collected. The CDK4 exon 2 and the complete coding region of the MC1R gene were sequenced. Results Eleven families carried the CDK4 R24H mutation whereas six families had the R24C mutation. The total number of subjects with verified melanoma was 103, with a median age at first melanoma diagnosis of 39 years. Forty-three (41.7%) subjects had developed multiple primary melanomas (MPM). A CDK4 mutation was found in 89 (including 62 melanoma cases) of 209 tested subjects. CDK4 positive family members (both melanoma cases and unaffected subjects) were more likely to have clinically atypical nevi than CDK4 negative family members (p<0.001). MPM subjects had a higher frequency of MC1R red hair colour variants compared with subjects with one tumour (p=0.010). Conclusion Our study shows that families with CDK4 germline mutations cannot be distinguished phenotypically from CDKN2A melanoma families, which are characterised by early onset of disease, increased occurrence of clinically atypical nevi, and development of MPM. In a clinical setting, the CDK4 gene should therefore always be examined when a melanoma family tests negative for CDKN2A mutation.

1 September 2010 in Cancer Epidemiology, Biomarkers & Prevention
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RBRichard Bränström
Richard Bränström
NKNadine Kasparian
Nadine Kasparian
YCYu-Mei Chang
Yu-Mei Chang
PAPaul Affleck
Paul Affleck
ATAad Tibben
Aad Tibben
YBYvonne Brandberg
Yvonne Brandberg
Background: The incidence of melanoma continues to increase in many countries, and primary prevention of melanoma includes avoidance of sunburn as well as adequate sun protection behavior. The aim of this study was to examine the prevalence of self-reported sun protection behaviors and sunburn in users of the Internet, and to identify the demographic, clinical, and attitudinal/motivational correlates of sun protection behaviors. Methods: Self-report data were gathered on behalf of the GenoMEL consortium using an online survey available in 10 different languages, and 8,178 individuals successfully completed at least 80% of survey items, with 73% of respondents from Europe, 12% from Australia, 7% from the United States, 2% from Israel, and 6% from other countries. Results: Half of all respondents and 27% of those with a previous melanoma reported at least one severe sunburn during the previous 12 months. The strongest factors associated with sun protection behavior were perceived barriers to protection (β = −0.44/β = −0.37), and respondents who reported a positive attitude toward suntans were less likely to protect (β = −0.16/β = −0.14). Reported use of protective clothing and shade, as well as avoidance of midday sun exposure, were more strongly related to reduced risk of sunburn than sunscreen use. Conclusions: Despite widespread dissemination of public health messages about the importance of sun protection, a substantial proportion of this international sample, including respondents with a previous melanoma, reported inadequate sun protection behaviors resulting in severe sunburn. Impact: Future strategies to decrease sunburn should target the practical, social, and psychological barriers associated with nonuptake of sun protection. Cancer Epidemiol Biomarkers Prev; 19(9); 2199–210. ©2010 AACR.

10 February 2012 in Pigment Cell & Melanoma Research
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Journal Article
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JDJohn R. Davies
John R. Davies
JRJuliette Randerson‐Moor
Juliette Randerson‐Moor
KKKairen Kukalizch
Kairen Kukalizch
MHMark Harland
Mark Harland
Rajiv KumarRajiv Kumar
Rajiv Kumar
JNJulia Newton‐Bishop
Julia Newton‐Bishop
Summary: Inherited MC1R variants modulate MITF transcription factor signaling, which in turn affects tumor cell proliferation, apoptosis, and DNA repair. The aim of this BioGenoMEL collaborative study in 10 melanoma cohorts was to test the hypothesis that inherited variants thereby moderate survival expectation. A survival analysis in the largest cohort (Leeds) was carried out adjusting for factors known to impact on survival. The results were then compared with data from nine smaller cohorts. The absence of any consensus MC1R alleles was associated with a significantly lower risk of death in the Leeds set (HR, 0.64; 95% CI, 0.46–0.89) and overall in the 10 data sets (HR, 0.78; 95% CI, 0.65–0.94) with some support from the nine smaller data sets considered together (HR, 0.83; 95% CI, 0.67–1.04). The data are suggestive of a survival benefit for inherited MC1R variants in melanoma patients.

20 February 2003 in Cytometry Part A
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Jekaterina ErenpreisaJekaterina Erenpreisa
Jekaterina Erenpreisa
JEJuris Erenpreiss
Juris Erenpreiss
TFTalivaldis Freivalds
Talivaldis Freivalds
MSMaija Slaidina
Maija Slaidina
RKRasma Krampe
Rasma Krampe
DPDace Pjanova
Dace Pjanova
Background: Sperm DNA integrity is of paramount importance in the prognosis of fertility. We applied image cytometry to a toluidine blue (TB) test we recently proposed.Methods: Sperm samples from 33 men were assayed for standard sperm parameters and classified as normal or abnormal. Sperm smears were subjected to the TB test, DNA denaturation testing with acridine orange (AO), and terminal deoxyuridine triphosphate biotin nick end labeling (TUNEL). In CCD image analysis, TB‐stained sperm cell heads were microscopically assigned to one of four color groups (dark, blue, light violet, and light blue). The optical densities of 6,600 cells in green and red CCD images were used to elaborate an algorithm for discrimination of these groups.Results: The proportions of sperm in TB color groups, as estimated with the developed image cytometry algorithm, correlated with microscopic features. The number of TB dark cells correlated with the number of AO‐red and TUNEL+ cells. The proportion of TB dark cells in normal samples did not exceed 35%. Light‐blue sperm cell heads prevailed in normal samples, whereas dark and blue sperm cell heads dominated in abnormal samples.Conclusions: The TB test was suitable for the assessment of sperm cell DNA integrity. The elaborated image cytometry algorithm can be used for this purpose and for finer determination of sperm nucleus status. Cytometry Part A 52A:19–27, 2003.

25 January 2019 in Genes
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KSKristine Salmina
Kristine Salmina
AHAnda Huna
Anda Huna
MKMartins Kalejs
Martins Kalejs
DPDace Pjanova
Dace Pjanova
HSHarry Scherthan
Harry Scherthan
Jekaterina ErenpreisaJekaterina Erenpreisa
Jekaterina Erenpreisa
Aneuploidy should compromise cellular proliferation but paradoxically favours tumour progression and poor prognosis. Here, we consider this paradox in terms of our most recent observations of chemo/radio-resistant cells undergoing reversible polyploidy. The latter perform the segregation of two parental groups of end-to-end linked dyads by pseudo-mitosis creating tetraploid cells through a dysfunctional spindle. This is followed by autokaryogamy and a homologous pairing preceding a bi-looped endo-prophase. The associated RAD51 and DMC1/γ-H2AX double-strand break repair foci are tandemly situated on the AURKB/REC8/kinetochore doublets along replicated chromosome loops, indicative of recombination events. MOS-associated REC8-positive peri-nucleolar centromere cluster organises a monopolar spindle. The process is completed by reduction divisions (bi-polar or by radial cytotomy including pedogamic exchanges) and by the release of secondary cells and/or the formation of an embryoid. Together this process preserves genomic integrity and chromosome pairing, while tolerating aneuploidy by by-passing the mitotic spindle checkpoint. Concurrently, it reduces the chromosome number and facilitates recombination that decreases the mutation load of aneuploidy and lethality in the chemo-resistant tumour cells. This cancer life-cycle has parallels both within the cycling polyploidy of the asexual life cycles of ancient unicellular protists and cleavage embryos of early multicellulars, supporting the atavistic theory of cancer.

1 May 2010 in European Journal Of Cancer Prevention
Verified
Journal Article
Closed access
RBRichard Bränström
Richard Bränström
YCYu-Mei Chang
Yu-Mei Chang
NKNadine Kasparian
Nadine Kasparian
PAPaul Affleck
Paul Affleck
ATAad Tibben
Aad Tibben
JNJulia Newton-Bishop
Julia Newton-Bishop
Cutaneous melanoma continues to increase in incidence in many countries, and intentional tanning is a risk factor for melanoma. The aim of this study was to understand how melanoma risk factors, perceived threat and preferences for a suntan relate to intentional tanning. Self-report data were collected on behalf of GenoMEL ( www.genomel.org ) from the general population using an online survey. A total of 8178 individuals completed the survey, with 72.8% of respondents being from Europe, 12.1% from Australia, 7.1% from the US, 2.5% from Israel and 5.5% from other countries. Seven percent of respondents had previously been diagnosed with melanoma and 8% had at least one first-degree relative with a previous melanoma. Overall, 70% reported some degree of intentional tanning during the past year, and 38% of respondents previously diagnosed with melanoma had intentionally tanned. The total number of risk factors was positively correlated with perceived risk of melanoma [correlation coefficient (ρ) = 0.27], and negatively correlated with intentional tanning (ρ = −0.16). Preference for a dark suntan was the strongest predictor of intentional tanning [regression coefficient (β) = 0.35, P<0.001], even in those with a previous melanoma (β = 0.33, P<0.01). A substantial proportion of participants reported having phenotypic and behavioural risk factors for melanoma. The preference regarding suntans seemed more important in the participants' decision to intentionally tan than their perceived risk of developing melanoma, and this finding was consistent among respondents from different countries. The drive to sunbathe to tan is a key factor to be moderated if melanoma incidence is to be reduced.