Cancer mortality and morbidity among patients with schizophrenia: A hospital-based cohort study, 1992-2020

OBJECTIVE

Due to the inconsistency of the evidence about the cancer risk among patients with schizophrenia, the aim of this study was to analyse cancer mortality and morbidity in patients with schizophrenia treated in a single centre in Lithuania during the study period of 1992-2020.

MATERIALS AND METHODS

A retrospective cohort study was conducted in Vilnius Republican Psychiatric Hospital, the biggest specialised psychiatric hospital in Lithuania, with approximately 5000 hospital admissions annually. The patients' cohort was established by identifying all patients with the diagnosis of schizophrenia (ICD-10 code F20) in the hospital database from 1 January 1992 until 31 December 2017. The cancer cases and cancer deaths in the cohort were identified in the Lithuanian Cancer Register through linkage procedures. The analysis of risk was based on a comparison of observed and expected numbers of cancers and deaths. Expected number of cancer cases were calculated by multiplication of the exact person-years under observation in the cohort by sex, calendar year and a 5-year age-group-specific national incidence and mortality rate. All statistical analyses were carried out using STATA 15 statistical software.

RESULTS

During the follow-up, out of 8553 patients, 673 cases of cancer were diagnosed in both sexes. Statistically significantly lower risk for overall cancer incidence was observed in men (SIR 0.74, 95% CI 0.66-0.83), but not in women (SIR 1.07, 95% CI 0.97-1.18). Statistically significant lower overall cancer mortality risk was observed in men (SMR 0.82, 95% CI 0.70-0.96), while in the women's group, risk of cancer deaths was significantly higher compared to the general population (SMR 1.28, 95% CI 1.11-1.48). We observed lower risk for pancreatic cancer (SIR 0.36, 95% CI 0.14-0.96), non-melanoma skin cancer (SIR 0.54, 95% CI 0.33-0.88) and prostate cancer (SIR 0.69, 95% CI 0.55-0.87) in men and higher risk for malignant neoplasm of liver (SIR 2.58, 95% CI 1.53-4.36) and skin melanoma (SIR 2.03, 95% CI 1.12-3.66) in men and for breast cancer (SIR 1.38, 95% CI 1.14-1.66) and corpus uteri cancer (SIR 1.56, 95% CI 1.18-2.07) in women.

CONCLUSIONS

The current results of our study indicate lower risk of overall cancer incidence and mortality in male patients with schizophrenia, while female patients had a higher mortality risk, alongside variations in the risk of different cancer types. This information is important not only for patients, but for healthcare specialists to develop effective disease-specific preventive interventions and programmes.

Efficacy of Sunitinib in Patients With Favorable and Intermediate Risk Metastatic Renal Cell Carcinoma - Lithuanian National Cancer Institute Experience

BACKGROUND/AIM

According to the European Society for Medical Oncology (ESMO) and National Comprehensive Cancer Network (NCCN) recommendations, sunitinib is one of the recommended regimens for favorable and intermediate-risk metastatic renal cell carcinoma (mRCC) patients. The objective of this study was to evaluate sunitinib efficacy as a first-line treatment for mRCC patients with favorable/intermediate prognostic risk in a real-world setting.

PATIENTS AND METHODS

Patients diagnosed with mRCC and confirmed as appropriate candidates for the first-line systemic treatment were included in this retrospective study. The prognostic risk was evaluated according to the model of the International Metastatic RCC Database Consortium (IMDC).

RESULTS

Patients received sunitinib as a first-line treatment. A total of 94 patients were enrolled from 2019 to the 2020and 67 of them were included in the detailed analysis. Median progression-free survival (PFS) was 23.4 (95%CI=17.3-29.5), and median overall survival (OS) was 66 months (95%CI=44.9-87.1). The age over 60 years was a significant negative predictor for PFS and OS. Regarding the IMDC model for disease risk prediction, the number of two risk factors in the intermediate risk group was a significant predictor for a shorter response to the first-line therapy.

CONCLUSION

Sunitinib is an effective tyrosine kinase inhibitor, which can be used as a first-line treatment in favorable/intermediate-risk groups of patients with mRCC, especially in countries where novel systemic treatment modalities are not yet available.

Sequential treatment of metastatic renal cell carcinoma patients after first-line vascular endothelial growth factor targeted therapy in a real-world setting: epidemiologic, noninterventional, retrospective-prospective cohort multicentre study

PURPOSE

The purpose of our study was to determine whether data on the clinical effectiveness of second-line therapy collected in a real-world setting provide additional valuable information on the optimal sequence of metastatic renal cell carcinoma (mRCC) treatment.

METHODS

Patients diagnosed with mRCC who were treated with at least one dose of first-line vascular endothelial growth factor (VEGF)-targeted therapy with either sunitinib or pazopanib and with at least one dose of second-line everolimus, axitinib, nivolumab, or cabozantinib were included. The efficacy of different treatment sequences was analyzed based on the time to the second objective disease progression (PFS2) and the time to the first objective disease progression (PFS).

RESULTS

Data from 172 subjects were available for analysis. PFS2 was 23.29 months. The 1-year PFS2 rate was 85.3%, and the 3-year PFS2 rate was 25.9%. The 1-year overall survival rate was 97.0%, and the 3-year overall survival rate was 78.6%. Patients with a lower IMDC prognostic risk group had a significantly (p < 0.001) longer PFS2. Patients with metastases in the liver had a shorter PFS2 than patients with metastases in the other sites (p = 0.024). Patients with metastases in the lungs and lymph nodes (p = 0.045) and patients with metastases in the liver and bones (p = 0.030) had lower PFS2 rates than patients with metastases in other sites.

CONCLUSIONS

Patients with a better IMDC prognosis have a longer PFS2. Metastases in the liver lead to a shorter PFS2 than metastases in other sites. One metastasis site means a longer PFS2 than 3 or more metastasis sites. Nephrectomy performed in an earlier stage of disease or metastatic setting means higher PFS and higher PFS2. No PFS2 difference was found between different treatment sequences of TKI-TKI or TKI-immune therapy.

Atezolizumab Retains Cellular Binding to Programmed Death Ligand 1 Following Aerosolization via Mesh Nebulizer

BACKGROUND/AIM

Cytotoxic inhalable drugs were shown to be advantageous in treating malignancies of the respiratory tract. However, these drugs have not always presented a safe profile and were reported to induce local adverse events. Protein-based anticancer drugs, such as immune checkpoint and vascular endothelial growth factor inhibitors, do not induce tissue injury, nor do they exhibit vesicant properties upon direct contact with tissues. Protein drugs are susceptible to the heat and stress encountered during droplet generation for delivery by nebulization. The aim of this study was to investigate the capacity of atezolizumab, an antibody to programmed death ligand 1, to bind target cells after nebulization with a vibrating mesh (VM) nebulizer.

MATERIALS AND METHODS

We compared Fourier-transformed infrared (FTIR) and Raman spectra of native atezolizumab (60 mg/ml) and its nebulized form following 10-min nebulization in a piezoceramic VM nebulizer. The binding of atezolizumab to DU-145 prostate cancer cells was evaluated using competitive blocking of anti-CD274 staining.

RESULTS

Nebulization did not induce Raman or FTIR spectral modification nor did it affect the binding capacity of atezolizumab. Conversely, heat-inactivated atezolizumab lost its cell-binding capacity and did not reduce anti-CD274 immunostaining. Native and nebulized atezolizumab displayed identical spectra, whereas the FTIR spectra of the heat-inactivated drug was significantly altered.

CONCLUSION

VM nebulization does not obliterate the functionality of the drug atezolizumab. The integrity of a nebulized form can be rapidly assessed by FTIR and Raman spectrometry.

Do the benefits of being a smoker hint at the existence of PD-1/PD-L1 sensitizers for patients on single-agent immunotherapy?

Multiple studies demonstrate significantly better therapeutics outcomes in smokers as compared with never smokers when single-agent immunotherapy is applied. Non-smoker patients usually need a combination of chemoimmunotherapy to achieve comparable or slightly better therapeutic results. This effect is thought to be due to tobacco product-induced upregulation of PD-L1/PD-1 expression and tumor mutational burden score. Genomic transformation, however, cannot entirely explain the upregulation of PD-L1/PL-1 expression in cells following short-term exposure to cytotoxic compounds. Cytotoxic drugs, crude tobacco products, benzo(a)pyrene, nicotine, and multiple other toxic compounds were shown to exhibit rapid PD-L1/PD-1 upregulation. A significant immunomodulatory effect of nicotine via acetylcholine receptors is well documented. However, nicotine activity rapidly subsides when the drug is withdrawn. We hypothesize that smoking cessation might mitigate the benefits of monoimmunotherapy for some patients. Further studies of the nicotinic acetylcholine receptor stimulus of immunocytes are needed and might lead to characterization and clinical implementation of new immunotherapy sensitizer products.

Retrospective cohort study of androgen deprivation therapy and the risk of diabetes in men with prostate cancer in Lithuania

OBJECTIVES

To examine the risk of type 2 diabetes in patients with prostate cancer and its association with androgen deprivation therapy (ADT).

DESIGN AND PARTICIPANTS

We performed a retrospective cohort study of patients diagnosed with prostate cancer in the Lithuanian male population between 1 January 2003 and 31 December 2012 who were identified through the Lithuanian Cancer registry. All prostate cancer cases were linked to the National Health Insurance Fund database to obtain information regarding the diagnosis of diabetes mellitus and information on prescriptions of antiandrogens and gonadotropin-releasing hormone (GnRH) agonists. Patients with prostate cancer were followed up until the diagnosis of type 2 diabetes, or 31 December 2017, or date of death, whichever came first. Cox proportional hazard models were used to estimate the risk of type 2 diabetes in patients with prostate cancer with or without ADT exposure.

RESULTS

27 580 men were diagnosed with prostate cancer, out of whom 14 502 (52.6%) did not receive ADT and 13 078 (47.4%) were treated with ADT. The incidence of type 2 diabetes for all patients with prostate cancer was 7.4/1000 person-years, for men on GnRH agonists 9.0/1000 person-years and 5.8/1000 person-years for men on antiandrogens. There was an increased risk of developing type 2 diabetes comparing ADT users and non-users (HR=1.49, 95% CI 1.34 to 1.66).

CONCLUSION

This study showed an increased risk of diabetes in patients with prostate cancer treated with ADT in comparison to ADT-free patient cohort. GnRH agonist users showed higher susceptibility, while the group on antiandrogen monotherapy showed no such increase.

Positive effect of metformin treatment in colorectal cancer patients with type 2 diabetes: national cohort study

We aimed to estimate colorectal cancer risk in patients with type 2 diabetes mellitus (T2DM) using metformin. Patients with colorectal cancer and diabetes from 2000 to 2012 were identified form Lithuanian Cancer Registry and the National Health Insurance Fund database. Standardized incidence ratios (SIRs) for colorectal cancers as a ratio of observed number of cancer cases in people with diabetes to the expected number of cancer cases in the underlying general population was calculated. We analysed 111 109 patients with diabetes. Overall, 1213 colorectal cancers were observed versus 954.91 expected within a period of observation entailing an SIR of 1.27 [95% confidence interval (CI): 1.20-1.34]. Significantly higher risk of colorectal cancer was found both in male and female patients with diabetes in all age groups. Higher risk was found for both colon and rectum cancers 1.36 (95% CI: 1.27-1.46) and 1.11 (95% CI: 1.01-1.22), respectively. There were no differences in risk over time since initial diabetes diagnosis. Never-users of metformin had twice higher risk of colorectal cancer compared to general population (SIR: 2.14, 95% CI: 1.95-2.35). Among metformin users, risk was lover (SIR: 1.47, 95% CI: 1.36-1.58) and colorectal cancer risk decreased with increasing cumulative dose of metformin (P < 0.001). Patients with T2DM had increased risk of colorectal cancer compared with the general Lithuanian population. Decreasing colorectal cancer risk with increasing cumulative dose of metformin indicates that metformin may be a protective agent for colorectal cancer development.

Trends in Incidence and Mortality of Skin Melanoma in Lithuania 1991-2015

Background. We aimed to investigate age-specific and sex-specific incidence trends of melanoma in Lithuania from 1991 to 2015. Methods. Analysis was based on data from the population-based Lithuanian Cancer Registry database for 1991–2015, and 6024 cases of skin melanoma were identified. Age-adjusted rates (ASRs) by sex and age group were calculated. Adjustment for ASRs was done using the old European standard population, where a total of three age groups were considered: 0–39, 40–59 and 60+. Additionally, the annual percent change (APC) was calculated, and 95% confidence intervals for APC were calculated. Results. Between 1991 and 2015, the overall melanoma rates increased by an annual percent change (APC) of 3.9% in men (95% CI, 3.6–4.1%) and 2.3% in women (95% CI, 2.1–2.5%). The highest incidences of new cutaneous melanoma cases were observed between old adults (60+) of both sexes, while the lowest incidence rates were observed in the young adult group (up to 39 years old), with the lowest APC (1.6% in males and 0.4% in females). The overall number of melanoma deaths during 1991 and 2015 increased from 64 to 103 deaths per year, and the age-standardized rate (ASR) increased 1.3 times (from 1.8 to 2.4). Conclusions. The incidence and mortality of skin melanoma seem to be increased in all age groups. These trends indicate that skin protection behavior is not sufficient in our population and more efforts need to be taken in order to decrease incidence and mortality rates.

The impact of metformin on survival in patients with melanoma-national cohort study

PURPOSE

The primary study outcome was melanoma-specific mortality in patients with type 2 diabetes mellitus (T2DM) using metformin.

METHODS

Data regarding patients were provided by the Lithuanian Cancer Registry and were linked with National Health Insurance Fund in accordance with unique personal identification numbers during the period of thirteen years.

RESULTS

About 2817 patients met eligibility criteria and were included in the retrospective cohort study. About 163 patients had pre-existing T2DM and 103 of them were treated with metformin. In the multivariable analysis, there was significant risk difference in melanoma-specific survival between diabetic, metformin-using patients, and nondiabetic patients (P=0.02) in favor of metformin users.

CONCLUSION

Melanoma patients with T2DM treated with metformin had lower risk of melanoma-specific mortality; however, prospective controlled studies are mandatory to confirm this finding.

Reproductive Factors and Breast Cancer Risk in Lithuanian Women: A Population-Based Cohort Study

Abstract. Background.

Although the relationship between reproductive factors and breast cancer is internationally proved, reliable data on former USSR countries are scarce. This study examines the association of parity, age at the first childbirth, number of children, and breast cancer risk in Lithuanian women.

Methods.

The study that included women from 40 to 79 years old was based on a dataset that was made up linking all records from the 2001 census, all cancer incidence records from the Lithuanian Cancer Registry and all death records from Statistics Lithuania between 6th April 2001 and 31st December 2009. Cox’s proportional hazards regression models were used to estimate the hazard ratios (HRs) for parity, age at the first childbirth, and number of children.

Results.

If compared to nulliparous women, parous women had a lower risk of breast cancer (HR=0.84, 95% CI 0.78–0.89) and this risk further decreased with an increasing number of children. Women who gave birth after the age of 25 had a significantly higher risk of breast cancer. This disadvantage became statistically insignificant or decreased after controlling for total number of children.

Conclusions.

Parity and age at the first childbirth are strong predictors of breast cancer risk among Lithu-anian women.

Skin Melanoma and Subsequent Risk of Prostate Cancer: A Lithuanian Cancer Registry Study

Emerging data indicates that melanoma may be linked to prostate cancer. We evaluated if the incidence of melanoma was associated with subsequent risk of prostate cancer (PC). We extracted data from the Lithuanian cancer registry from 1993 to 2012. We calculated the standardized incidence ratios (SIRs) for PC as a ratio of observed number of cancer cases in people with previous melanoma diagnosis to the expected number of cancer cases in the underlying general population. Therein, 95% confidence intervals for the SIRs were estimated assuming the number of observed cancer cases follows the Poisson distribution. Overall, 65 PCs were observed versus 52.5 expected (SIR 1.24; 95% CI: 0.97–1.58) within a period of 24 years. A significantly increased risk of PC was found in patients with melanoma diagnosis over 70 years (SIR 1.62; 95% CI: 1.11–2.39) and in two periods of diagnosis (SIRs 1.76 and 1.62 in 1993–1997 and 2009–2012, respectively). A significantly increased risk was also found five to nine years after melanoma diagnosis (SIR 1.58; 95% CI: 1.05–2.38). Further studies are needed to evaluate the relationship between melanoma and subsequent risk of prostate cancer.

Suicide risk among colorectal cancer patients in Lithuania

PURPOSE

We aimed to estimate suicide risk among colorectal cancer patients in the country showing the highest suicide rates among developed countries.

METHODS

Patients with colorectal cancer diagnosed between 1998 and 2012 were identified from the Lithuanian Cancer Registry. Standardised mortality ratios (SMRs) for suicide were calculated for patients diagnosed with cancer in Lithuania, relative to suicide rates in the general population.

RESULTS

Twenty thousand seven hundred sixty-five primary colorectal cancer cases diagnosed between 1998 and 2012 were extracted from the database. Among 19,409 first primary colorectal cancer patients, we identified 67 suicides and the expected number of suicides calculated from general population was 41.4 in this cohort, resulting in an SMR of 1.62 for both sexes (95% CI, 1.27-2.06). A higher suicide risk was found for women (SMR 2.15; 95% CI 1.35-3.41), than for men (SMR 1.48; 95% CI 1.12-1.96). The suicide risk was almost twice higher in patients 60 and older, with highest increase in the oldest patients (SMR 2.12, 95% CI 1.01-4.46). The risk of suicide was not significantly elevated in colorectal cancer patients with localised tumours, but there was a fourfold increase in risk in patients with stage IV tumours. Compared with the general population, the risk of suicide among colorectal cancer patients was four times higher during the first 3 months after diagnosis and decreased thereafter.

CONCLUSIONS

The patients with colorectal cancer have a higher rate of suicide compared with the general Lithuanian population. Sex, age, advanced rectal cancer and distant spread of disease were the main predictors of suicide among colorectal cancer patients.

Paclitaxel with or without trametinib or pazopanib in advanced wild-type BRAF melanoma (PACMEL): a multicentre, open-label, randomised, controlled phase II trial

BACKGROUND

Advanced melanoma treatments often rely on immunotherapy or targeting mutations, with few treatment options for wild-type BRAF (BRAF-wt) melanoma. However, the mitogen-activated protein kinase pathway is activated in most melanoma, including BRAF-wt. We assessed whether inhibiting this pathway by adding kinase inhibitors trametinib or pazopanib to paclitaxel chemotherapy improved outcomes in patients with advanced BRAF-wt melanoma in a phase II, randomised and open-label trial.

PATIENTS AND METHODS

Patients were randomised (1 : 1 : 1) to paclitaxel alone or with trametinib or pazopanib. Paclitaxel was given for a maximum of six cycles, while 2 mg trametinib and 800 mg pazopanib were administered orally once daily until disease progression or unacceptable toxicity. Participants and investigators were unblinded. The primary end point was progression-free survival (PFS). Key secondary end points included overall survival (OS) and objective response rate (ORR).

RESULTS

Participants were randomised to paclitaxel alone (n = 38), paclitaxel and trametinib (n = 36), or paclitaxel and pazopanib (n = 37). Adding trametinib significantly improved 6-month PFS [time ratio (TR), 1.47; 90% confidence interval (CI) 1.08-2.01, P = 0.04] and ORR (42% versus 13%; P = 0.01) but had no effect on OS (P = 0.25). Adding pazopanib did not benefit 6-month PFS; (TR 1.36; 90% CI 0.96-1.93; P = 0.14), ORR, or OS. Toxicity increased in both combination arms.

CONCLUSION

In this phase II trial, adding trametinib to paclitaxel chemotherapy for BRAF-wt melanoma improved PFS and substantially increased ORR but did not impact OS.This study was registered with the EU Clinical Trials Register, EudraCT number 2011-002545-35, and with the ISRCTN registry, number 43327231.

Breast Cancer Screening Program in Lithuania: Interval Cancers and Program Sensitivity After 7 Years of Mammography Screening

OBJECTIVE

Analysis of interval cancers is critical in determining the sensitivity of screening and represents an objective measure of the quality of mammography screening program (MSP).

METHODS

Period analyzed: from 2006 to 2012. The rate of screen-detected, interval cancers and program sensitivity were measured. A comparison of screen-detected and interval cancers was performed.

RESULTS

During the period of the study, 429 473 women were screened and 1297 were found to have cancer. The overall screen-detected cancer rate was 30.2 per 10 000 women screened. Four hundred thirty-one case of interval cancers have occurred during the period of the study. The interval cancer ratio (ICR) was 0.25. Overall sensitivity of MSP amounted to 75.1%. Slightly lower sensitivity was found among the youngest age-group, especially for those with lobular cancers. Interval cancers were bigger in size, more often with metastases in lymph nodes, than screen-detected cancers, but these differences were not statistically significant.

CONCLUSIONS

Overall program sensitivity in Lithuania is about 75%, ICR is 0.25, and these parameters are comparable to other European countries.

Survival and time interval from surgery to the start of chemotherapy for patients with stage II and III colon cancer

Background.

Usually adjuvant chemotherapy is started within 12 weeks of surgery, but the evidence on the commencing time is lacking. Our aim was to investigate the association of initiating post-surgery treatment within six weeks vs. six to ten weeks vs. more than ten weeks with survival.

Methods.

We analysed the association of treatment and its timing with survival among patients who were diagnosed and underwent surgery for stage II or III colon cancer from 2012 to 2013 at the National Cancer Institute, Lithuania.

Results.

Of the 86 patients, 78% were still alive on December 31, 2013. Patients who received chemotherapy within six weeks after surgery were more likely to survive. However, those who received chemotherapy 6–10 weeks after surgery had better survival (p – 0.014, hazard ratio 0.80, 95% CI 0.60–0.99) than those who began chemotherapy treatment more than ten weeks after surgery (p – 0.173 hazard ratio 0.55, 95% CI 0.12–0.99).

Conclusions.

The results from this study show that optimal timing of adjuvant chemotherapy for patients with resected colon cancer within six weeks and associated with better survival.

Diagnostic accuracy of procalcitonin, interleukin-6 and interleukin-8 for predicting Gram-negative bacteremia in febrile neutropenia patients with acute lymphoblastic leukemia

Background. Currently available biomarkers are not specific and sensitive enough for early detection of bacterial infection in patients with cancer who have febrile neutropenia. The objective of this study was to assess diagnostic accuracy of interleukin-6 (IL-6), interleukin-8 (IL-8) and procalcitonin (PCT) in the identification of Gram-negative bacteremia at the beginning of a febrile episode in pediatric oncology patients with acute lymphoblastic leukemia (ALL). Methods. A total of 40 episodes of febrile neutropenia in 27 childhood cancer patients were enrolled in this study. Serum samples were collected at presentation after confirmation of febrile neutropenia and analyzed according to the recommendations of manufacturers. Patients were classified into Gram-negative bacteremia (GNB) and fever of unknown origin (FUO) groups. Results. The median concentration of IL-6, IL-8 and PCT were higher in the GNB group compared to the FUO group (65.4  vs.  409.0  pg/ml, P  =  0.0025; 166.0  vs.  883.0  pg/ml, P  =  0.0002; 0.27  vs.  0.44  ng/ml, P = 0.0169, respectively). The areas under the curves (AUCs) for both IL-6 and IL-8 were 0.94 and 0.93, respectively, indicating that these cytokines discriminated patients with Gram-negative bacteremia with excellent accuracy, whereas PCT had lower diagnostic accuracy (AUC = 0.76). Conclusions. IL-6 and IL-8 evaluation might be used as an additional diagnostic tool for the prediction of Gram-negative bacteremia in pediatric patients with ALL during febrile neutropenia episodes.

Increased interleukin-10 levels correlate with bacteremia and sepsis in febrile neutropenia pediatric oncology patients

BACKGROUND

Early diagnosis of bacteremia and sepsis in pediatric oncology patients with febrile neutropenia still remains unresolved task due to lack of sensitive and specific laboratory markers particularly at the beginning of the infectious process. The objective of our study was to assess the potentiality of interleukin-10 (IL-10) to predict or exclude bacteremia or sepsis at the beginning of febrile episode in childhood oncology patients.

METHODS

A total of 36 febrile neutropenic episodes in 24 children were studied. Serum samples were collected after confirmation of febrile neutropenia and analyzed using automated random access analyzer.

RESULTS

The sensitivity of IL-10 was 73% and specificity - 92% (cut-off=18pg/ml, area under the curve - 0.87, 95% CI for sensitivity 39-94%, 95% CI for specificity 74-99%) with negative predictive value (NPV) - 83%.

CONCLUSIONS

IL-10 evaluation might be used as an additional diagnostic tool for clinicians in excluding bacteremia or clinical sepsis in oncology patients with febrile neutropenia because of high NPV and specificity.

Genotypes of Helicobacter pylori in Lithuanian families

BACKGROUND

Infection by Helicobacter pylori is very common in Eastern Europe, but the genotypes of predominant strains and prevalence of single vs. multiple infection in this geographic region have not been much studied.

MATERIALS AND METHODS

H. pylori was cultured from 13 Lithuanians belonging to six families, and characterized by arbitrarily primed PCR (RAPD) DNA fingerprinting, and by hybridization and PCR tests for polymorphic virulence-associated and neutral genetic markers.

RESULTS

Eleven distinct strains were identified: seven carried the cag pathogenicity island (PAI) and the s1 (generally toxigenic) allele of the vacuolating cytotoxin gene (vacA); the other four were cag- and carried the vacA s2 (nontoxigenic) allele; five of the seven vacA s1 strains carried an m1 middle region allele of vacA, whereas all other strains carried m2 alleles, which are generally less toxigenic; four strains carried the virulence-associated iceA1 gene, and the other seven carried the completely unrelated iceA2 gene at the same locus. Insertion sequences IS605 and IS606 and a plasmid replication gene (repA) were also found in some strains. RAPD fingerprinting identified a mixed infection in just one of the 13 persons. In two families, two of the members harbored the same strain, whereas in the other four families each member tested carried a different strain. Resistance to metronidazole (Mtz) was found in two persons; each of them also carried MtzS strains that were indistinguishable from the coresident MtzR strain by RAPD fingerprinting, and that were thus closely related in overall genotype.

CONCLUSION

The distribution of genotypes of Lithuanian H. pylori strains resembles that seen in Western Europe. This finding has important implications for understanding modes of H. pylori transmission and evolution.