Current Insights into Interethnic Variability in Testicular Cancers: Population Pharmacogenetics, Clinical Trials, Genetic Basis of Chemotherapy- Induced Toxicities and Molecular Signal Transduction

Testicular cancer is an aggressive malignancy with a rising incidence rate across the globe. Testicular germ cell tumors are the most commonly diagnosed cancers, and surgical removal of the testes is often a radical necessity along with chemotherapy and radiotherapy. While seminomas are receptive to radiotherapy as well as chemotherapy, non-seminomatous germ cell tumors respond to chemotherapy only. Due to the singular nature of testicular cancers with associated orchiectomy and mortality, it is important to study the molecular basis and genetic underpinnings of this group of cancers across male populations globally. In this review, we shed light on the population pharmacogenetics of testicular cancer, pediatric and adult tumors, current clinical trials, genetic determinants of chemotherapy-induced toxicity in testicular cancer, as well as the molecular signal transduction pathways operating in this malignancy. Taken together, our discussions will help in enhancing our understanding of genetic factors in testicular carcinogenesis and chemotherapy-induced toxicity, augment our knowledge of this aggressive cancer at the cellular and molecular level, as well as improve precision medicine approaches to combat this disease.

Late adverse effects and quality of life in survivors of testicular germ cell tumour

Currently, ~95% of patients with testicular germ cell tumour (TGCT) are cured, resulting in an increasing number of TGCT survivors. Although cured, these men face potential late adverse effects and reduced quality of life. Survivors face a twofold increased risk of second malignant neoplasms after chemotherapy and radiotherapy, with evidence of dose-dependent associations. For survivors managed with surveillance or treated with radiotherapy, the risk of cardiovascular disease (CVD) is comparable to the risk in the general population, whereas treatment with chemotherapy increases the risk of life-threatening CVD, especially during treatment and after 10 years of follow-up. Other adverse effects are organ-related toxicities such as neuropathy and ototoxicity. Pulmonary and renal impairment in patients with TGCT treated with chemotherapy is limited. Survivors of TGCT might experience psychosocial distress including anxiety disorders, fear of cancer recurrence and TGCT-specific issues, such as sexual dysfunction. Late adverse effects can be avoided in most patients with stage I disease if followed on a surveillance programme. However, patients with disseminated disease can experience toxicities associated with radiotherapy and chemotherapy, and/or adverse effects related to surgery for residual disease. The severity of adverse effects increases with dose of both chemotherapy and radiotherapy. This Review discusses the most recent data concerning the late adverse effects of today's standard treatments for TGCT.

Bleomycin hydrolase regulates the release of chemokines important for inflammation and wound healing by keratinocytes

Bleomycin hydrolase (BLMH) is a well-conserved cysteine protease widely expressed in several mammalian tissues. In skin, which contains high levels of BLMH, this protease is involved in the degradation of citrullinated filaggrin monomers into free amino acids important for skin hydration. Interestingly, the expression and activity of BLMH is reduced in patients with atopic dermatitis (AD) and psoriasis, and BLMH knockout mice acquire tail dermatitis. Apart from its already known function, we have discovered a novel role of BLMH in the regulation of inflammatory chemokines and wound healing. We show that lowered BLMH levels in keratinocytes result in increased release of the pro-inflammatory chemokines CXCL8 and GROα, which are upregulated in skin from AD patients compared to healthy individuals. Conditioned media from keratinocytes expressing low levels of BLMH increased chemotaxis by neutrophils and caused a delayed wound healing in the presence of low-level TNFα. This defective wound healing was improved by blocking the shared receptor of CXCL8 and GROα, namely CXCR2, using a specific receptor antagonist. Collectively, our results present a novel function of BLMH in regulating the secretion of chemokines involved in inflammation and wound healing in human keratinocytes.

Imaging of Metastatic Germ Cell Tumors in Male Patients From Initial Diagnosis to Treatment-Related Toxicities: A Primer for Radiologists

OBJECTIVE. This review describes the influence of histology and metastatic sites on prognosis in male patients with metastatic germ cell tumors (GCTs) and explains the role imaging in assessing therapeutic response, residual disease, recurrence, sand treatment-related toxicities. CONCLUSION. Seminomatous and nonseminomatous GCTs differ in imaging appearance, pattern of spread, and prognosis, and an organ-based approach is helpful in prognostication. Multimodality imaging aids in accurate staging, prognostication, characterization of treatment response, and identification of therapy-related toxicity.

A Novel Gene Underlies Bleomycin-Response Variation in Caenorhabditis elegans

Bleomycin is a powerful chemotherapeutic drug used to treat a variety of cancers. However, individual patients vary in their responses to bleomycin. The identification of genetic differences that underlie this response variation could improve treatment outcomes by tailoring bleomycin dosages to each patient. We used the model organism Caenorhabditis elegans to identify genetic determinants of bleomycin-response differences by performing linkage mapping on recombinants derived from a cross between the laboratory strain (N2) and a wild strain (CB4856). This approach identified a small genomic region on chromosome V that underlies bleomycin-response variation. Using near-isogenic lines, and strains with CRISPR-Cas9 mediated deletions and allele replacements, we discovered that a novel nematode-specific gene (scb-1) is required for bleomycin resistance. Although the mechanism by which this gene causes variation in bleomycin responses is unknown, we suggest that a rare variant present in the CB4856 strain might cause differences in the potential stress-response function of scb-1 between the N2 and CB4856 strains, thereby leading to differences in bleomycin resistance.

Testicular germ cell tumor: a comprehensive review

Testicular tumors are the most common tumors in adolescent and young men and germ cell tumors (TGCTs) account for most of all testicular cancers. Increasing incidence of TGCTs among males provides strong motivation to understand its biological and genetic basis. Gains of chromosome arm 12p and aneuploidy are nearly universal in TGCTs, but TGCTs have low point mutation rate. It is thought that TGCTs develop from premalignant intratubular germ cell neoplasia that is believed to arise from the failure of normal maturation of gonocytes during fetal or postnatal development. Progression toward invasive TGCTs (seminoma and nonseminoma) then occurs after puberty. Both inherited genetic factors and environmental risk factors emerge as important contributors to TGCT susceptibility. Genome-wide association studies have so far identified more than 30 risk loci for TGCTs, suggesting that a polygenic model fits better with the genetic landscape of the disease. Despite high cure rates because of its particular sensitivity to platinum-based chemotherapy, exploration of mechanisms underlying the occurrence, progression, metastasis, recurrence, chemotherapeutic resistance, early diagnosis and optional clinical therapeutics without long-term side effects are urgently needed to reduce the cancer burden in this underserved age group. Herein, we present an up-to-date review on clinical challenges, origin and progression, risk factors, TGCT mouse models, serum diagnostic markers, resistance mechanisms, miRNA regulation, and database resources of TGCTs. We appeal that more attention should be paid to the basic research and clinical diagnosis and treatment of TGCTs.

Association Study Among Candidate Genetic Polymorphisms and Chemotherapy-Related Severe Toxicity in Testicular Cancer Patients

Testicular cancer is one of the most commonly occurring malignant tumors in young men with fourfold higher rate of incidence and threefold higher mortality rates in Chile than the average global rates. Surgery is the initial line of treatment for testicular cancers, and is generally followed by chemotherapy, usually with combinations of bleomycin, etoposide, and cisplatin (BEP). However, the adverse effects of chemotherapy vary significantly among individuals; therefore, the present study explored the association of functionally significant allelic variations in genes related to the pharmacokinetics/pharmacodynamics of BEP and DNA repair enzymes with chemotherapy-induced toxicity in BEP-treated testicular cancer patients. We prospectively recruited 119 patients diagnosed with testicular cancer from 2010 to 2017. Genetic polymorphisms were analyzed using PCR and/or qPCR with TaqMan^®probes. Toxicity was evaluated based on the Common Terminology Criteria for Adverse Events, v4.03. After univariate analyses to define more relevant genetic variants (p < 0.2) and clinical conditions in relation to severe (III–IV) adverse drug reactions (ADRs), stepwise forward multivariate logistic regression analyses were performed. As expected, the main severe ADRs associated with the non-genetic variables were hematological (neutropenia and leukopenia). Univariate statistical analyses revealed that patients with ERCC2 rs13181 T/G and/or CYP3A4 rs2740574 A/G genotypes are more likely to develop alopecia; patients with ERCC2 rs238406 C/C genotype may develop leukopenia, and patients with GSTT1-null genotype could develop lymphocytopenia (III–IV). Patients with ERCC2 rs1799793 A/A were at risk of developing severe anemia. The BLMH rs1050565 G/G genotype was found to be associated with pain, and the GSTP1 G/G genotype was linked infection (p < 0.05). Multivariate analysis showed an association between specific ERCC1/2 genotypes and cumulative dose of BEP drugs with the appearance of severe leukopenia and/or febrile neutropenia. Grades III–IV vomiting, nausea, and alopecia could be partly explained by the presence of specific ERCC1/2, MDR1, GSTP1, and BLMH genotypes (p < 0.05). Hence, we provide evidence for the usefulness of pharmacogenetics as a tool for predicting severe ADRs in testicular cancer patients treated with BEP chemotherapy.

Nrf2 mediates the resistance of human A549 and HepG2 cancer cells to boningmycin, a new antitumor antibiotic, in vitro through regulation of glutathione levels

NF-E2-related factor 2 (Nrf2) is a transcription factor and a pivotal factor in the induction of the cell defense system. Recent reports show that Nrf2 plays critical roles in tumor heterogeneity and drug resistance. In the present study we investigated whether and how Nrf2 mediated the resistance of human cancer cells to boningmycin (BON), a new antitumor antibiotic of the bleomycin family. We showed that in the expression levels of Nrf2 in human non-small lung cancer A549 cells were much higher than those in human hepatoblastoma HepG2 cells, and their resistance to BON was opposite to Nrf2 expression (the IC₅₀values of BON in A549 cells and HepG2 cells were 5.97 and 0.61 μmol/L, respectively). Similar results were observed with the anticancer agent cisdiamminedichloroplatinum (DDP), which was used as a positive control. In A549 cells, Nrf2 mRNA knockdown significantly increased their susceptibilities to BON and DDP. An enhanced resistance to BON and DDP was observed in HepG2 cells after overexpression of the wild-type Nrf2 protein. Treatment with a specific Nrf2 inhibitor, luteolin, significantly sensitized A549 cells to BON and DDP and increased BON- or DDP-induced apoptosis. The total levels of glutathione (GSH), the final product of the Nrf2 signaling pathway, were much higher in A549 cells than those in HepG2 cells. Supplementation of GSH in HepG2 cells significantly decreased their susceptibility to BON and DDP, wheras depleting GSH with the specific inhibitor L-buthionine sulfoximine in A549 cells significantly increased their susceptibility to BON and DDP. Our results demonstrate that Nrf2 mediates the resistance to BON through regulating glutathione levels in A549 cells and HepG2 cells.

Adverse Effects of Vincristine Chemotherapy on Cell Changes in Seminiferous Tubules and Cetrorelix GnRH Antagonist Inhibitory Effects in Mice

The present study was designed to determine changes in spermatogenesis in adult mice after an intraperitoneal injection of vincristine. The effect of a GnRH antagonist synchronous to chemotherapy, which might protect spermatogenesis by halting cell division in spermatogenic cells, was also investigated.

Frequency distribution of BLMH, XPO5 and HFE gene polymorphisms in the South Indian population and their association with Hodgkin Lymphoma

BACKGROUND

Hodgkin lymphoma, a highly curable malignancy is currently treated with an adriamycin, bleomycin (BLM), vinblastine, and dacarbazine (ABVD) regimen. BLM-induced pulmonary toxicity (BPT) is one of the dose-limiting toxicities. Previous reports have revealed that genetic variants rs1050565, rs11077, and rs1800562 are involved in the development of BPT. These results cannot be extrapolated to the South Indian population because of their ethnic difference. This study aimed to determine the frequency of rs1050565, rs11077, and rs1800562 variants in South Indian healthy individuals and Hodgkin lymphoma cases. These frequencies were compared with 1000 genome populations' data. We also assessed if these variants modified the risk to Hodgkin lymphoma.

MATERIAL AND METHODS

A total of 200 healthy individuals and 101 cases with Hodgkin lymphoma were recruited for this case-control study after ethical approval. Blood samples were collected from the study participants and DNA was extracted. Genotyping of rs1050565, rs11077, and rs1800562 variants was done using real-time polymerase chain reaction. A chi-square test was used to assess the differences in genotype frequency data between cases and controls.

RESULTS

The minor allele frequencies of rs1050565 and rs11077 were 4.3% and 39%, respectively, whereas all the individuals were wild-type for rs1800562 mutation. The frequencies significantly differed from 1000 genome data. The variants did not alter the risk for Hodgkin lymphoma.

CONCLUSIONS

We determined the frequencies of rs1050565, rs11077, and rs1800562 variants in South Indian healthy individuals, and the frequencies differed significantly from 1000 genome populations. We also found that the studied polymorphisms are not associated with Hodgkin lymphoma risk in the South Indian population.

Deep sequencing reveals the molecular pathology characteristics between primary uterine leiomyoma and pulmonary benign metastasizing leiomyoma

PURPOSE

Pulmonary benign metastasizing leiomyoma (PBML), a rare condition of smooth muscle tumor, originates from women with a history of uterine leiomyoma (LM). Numerous genetic studies of uterine LM have been reported; however, there are few cytogenetic and molecular descriptions of PBML. Therefore, molecular subtyping is necessary to understand the pathogenesis of metastasizing sites.

METHODS

Driver gene exon-capture sequencing was performed on one patient's peripheral blood, paraffin samples from primary uterine LM, and lung metastasizing leiomyoma 8 years later.

RESULTS

The results showed that the same missense mutations of BLMH, LRP2, MED12, SMAD2, and UGT1A8 were concurrently mutated in the primary uterine LM and the PBML. Moreover, a splice mutation of PTEN (c.492+1G>A) was uniquely identified in the lung metastasis of the patient.

CONCLUSION

This study indicates that the metastatic lung lesions were derived from the same malignant cell clone of uterine LMs and later acquired the novel driver mutations in the evolution of the tumor. In addition, driver gene sequencing can discriminate somatic driver mutations as biological indicators of potential malignant leiomyoma and can identify pathogenic variation driver mutations, which could be used for individualized therapy.

Thromboprophylaxis and the route of administration of chemotherapy in testicular cancer patients in German-speaking countries

PURPOSE

Due to the excellent cure rates for testicular cancer (TC), focus has shifted towards decreasing therapy-related morbidities. Thrombosis is a frequent complication of cisplatin chemotherapy. Furthermore, the optimal route of administration for chemotherapy is still under debate. The purpose of this study was to assess the patterns of care concerning dosing and duration of thromboprophylaxis currently utilized in TC patients in German-speaking countries as well as the route of chemotherapy administration.

METHODS

A standardized questionnaire was sent to all members of the German TC Study Group (GTCSG) and to all the urological university hospitals in Germany. The questionnaire was also sent to the oncologic clinics at those universities where urologists do not administer chemotherapy.

RESULTS

The response rate was 87% (55/63). Prophylactic anticoagulation with low-molecular-weight heparin (LMWH) was administered in 94% of the clinics. The dosing of LMWH was prophylactic (85%), high prophylactic (adjusted to bodyweight) (7%), or risk adapted (9%). After completion of chemotherapy, anticoagulation was continued in 15 clinics (33%) for 2 to 24 weeks, while the remainder stopped the LMWH upon cessation of chemotherapy. Chemotherapy was administered via central venous access in 59%, peripheral IV in 27%, or both in 14% of the clinics.

CONCLUSIONS

Most of the institutions performed some form of thromboprophylaxis, although the modes of application varied by institution type and amongst the urologists and oncologists. Prospective studies are needed to evaluate the incidence, date of occurrence, and risk factors of venous thrombosis during TC chemotherapy to provide a recommendation concerning prophylactic anticoagulation.

Genotypes Affecting the Pharmacokinetics of Anticancer Drugs

Cancer treatment is becoming more and more individually based as a result of the large inter-individual differences that exist in treatment outcome and toxicity when patients are treated using population-based drug doses. Polymorphisms in genes encoding drug-metabolizing enzymes and transporters can significantly influence uptake, metabolism, and elimination of anticancer drugs. As a result, the altered pharmacokinetics can greatly influence drug efficacy and toxicity. Pharmacogenetic screening and/or drug-specific phenotyping of cancer patients eligible for treatment with chemotherapeutic drugs, prior to the start of anticancer treatment, can identify patients with tumors that are likely to be responsive or resistant to the proposed drugs. Similarly, the identification of patients with an increased risk of developing toxicity would allow either dose adaptation or the application of other targeted therapies. This review focuses on the role of genetic polymorphisms significantly altering the pharmacokinetics of anticancer drugs. Polymorphisms in DPYD, TPMT, and UGT1A1 have been described that have a major impact on the pharmacokinetics of 5-fluorouracil, mercaptopurine, and irinotecan, respectively. For other drugs, however, the association of polymorphisms with pharmacokinetics is less clear. To date, the influence of genetic variations on the pharmacokinetics of the increasingly used monoclonal antibodies has hardly been investigated. Some studies indicate that genes encoding the Fcγ-receptor family are of interest, but more research is needed to establish if screening before the start of therapy is beneficial. Considering the profound impact of polymorphisms in drug transporters and drug-metabolizing enzymes on the pharmacokinetics of chemotherapeutic drugs and hence, their toxicity and efficacy, pharmacogenetic and pharmacokinetic profiling should become the standard of care.

Effect of Bleomycin Administration on the Development of Pulmonary Toxicity in Patients With Metastatic Germ Cell Tumors Receiving First-Line Chemotherapy: A Meta-Analysis of Randomized Studies

BACKGROUND

Limited information is available about the effect of bleomycin administration on the development of pulmonary toxicity in metastatic germ cell tumors (GCT).

PATIENTS AND METHODS

A literature search was conducted to identify randomized trials of first-line chemotherapy for GCT. We conducted univariate and multivariate analyses using random effects models to evaluate the predictive role of bleomycin administration in the development of all Grade and Grade 3 to 4 (G3-4) pulmonary toxicity. The results were adjusted for length of follow-up, prognostic risk group, year of treatment, presence of lung metastases, and primary mediastinal GCT.

RESULTS

Fifty-three study arms of 25 phase II and III trials encompassing 6498 patients were selected: 40 that used bleomycin (n = 5093) and 13 that did not (n = 1405). The pooled probability of all-Grade pulmonary toxicity in the bleomycin and nonbleomycin arms was 11.7% (95% confidence interval [CI], 8.4%-16.0%) and 1.7% (95% CI, 0.7%-4.2%), respectively. Univariate analysis indicated that bleomycin administration was associated with the incidence of all-Grade (odds ratio [OR], 7.57; 95% CI, 2.84-20.18; Wald test P < .001) and G3-4 pulmonary toxicity (OR, 5.19; 95% CI, 1.57-17.16; P = .007). Multivariate analysis showed a significant association of bleomycin administration with the incidence of all-Grade pulmonary toxicity (OR, 4.14; 95% CI, 1.36-12.59; P = .012) and a trend toward significance for G3-4 toxicity (OR, 2.24; 95% CI, 0.91-5.51; P = .080).

CONCLUSION

We quantified the bleomycin-associated effect on the development of pulmonary toxicity in patients with GCT who received first-line chemotherapy. This information might be useful for planning clinical trials aimed at reducing chemotherapy as well as to inform patients in the clinic.

Bleomycin-Induced Pneumonitis in the Treatment of Ovarian Sex Cord-Stromal Tumors: A Systematic Review and Meta-analysis

OBJECTIVE

Adult ovarian sex cord-stromal tumors (SCSTs) are a rare histological subtype of ovarian cancer associated with a favorable prognosis. Bleomycin-containing regimens are standards of care, although pneumonitis may cause potentially fatal dose-limiting toxicity. We aimed to evaluate the safety of bleomycin in SCST treatment.

METHODS

We performed a systematic literature review of all studies of bleomycin therapy for SCSTs that were referenced in MEDLINE (PubMed), EMBASE, and Cochrane Central Register of Controlled Trials and published from 1986 to 2014.

RESULTS

Eight studies totaling 221 patients were included. Rates of pneumonitis (7.7%; 95% confidence interval, 4.2-11.2) and mortality (1.8%; 95% confidence interval, 0.1-3.6) related to bleomycin were significant. However, these results were very similar to those reported for men who were treated with bleomycin for a male germ cell tumor, suggesting that women with ovarian SCSTs are not particularly vulnerable to bleomycin lung toxicity. The main risk factors of bleomycin-induced pneumonitis are high cumulative bleomycin dose (>400 U or mg), age older than 40 years, and impaired renal function. Whether granulocyte colony-stimulating factor is a risk factor remains controversial.

CONCLUSIONS

Bleomycin-induced pneumonitis frequently occurs in patients with SCSTs and lacks effective treatment. Prevention lies in limiting cumulative bleomycin dose, monitoring pulmonary function during treatment, discontinuing bleomycin at the onset of pulmonary symptoms or if pulmonary function is impaired, and avoiding bleomycin in older patients.

Effect of Bleomycin Hydrolase Gene Polymorphism on Late Pulmonary Complications of Treatment for Hodgkin Lymphoma

Background

Bleomycin hydrolase (BLMH), an enzyme that inactivates bleomycin, may be a potential candidate that could influence pulmonary function in ABVD (doxorubicin, bleomycin, vinblastin, dacarbasine)–treated Hodgkin lymphoma (HL) patients.

Patients and Methods

We hypothesized that the BLMH gene SNP A1450G (rs1050565) influences BLMH activity and late pulmonary toxicity. St. George Respiratory Questionnaire, lung scintigraphy and spirometry were used to determine lung function. TaqMan genotyping assay was used to determine genotype distribution of 131 previously treated HL patients.

Results

Significantly more favorable results were seen in the wild-type A/A genotype group than those in the group containing the mutated allele: A/G+G/G in retrospective pulmonary tests of ABVD treated patients.

Conclusion

Besides limitations of the current study, bleomycin pharmacokinetics should be further evaluated in patients with BLMH variations, hence identify those cases even in the frontline setting, where bleomycin should be omitted and replaced with targeted therapy.

[Consortium for detection and management of lung damage induced by bleomycin]

Bleomycin is a cytotoxic antibiotic and a component of chemotherapy regimens of germ cell tumors and lymphoma. Bleomycin lung injuries occur in 10% of patients, and lead to severe interstitial pneumonia in 3% of patients. Pulmonary toxicity is related to endothelial cells injury induce by free radicals and inflammatory cytokines. Diagnosis of bleomycin-induced lung toxicity is based on the combination of clinical and radiological features, and requires to rule out differential diagnoses including pneumocystis. "Bleomycin-induced pneumonitis" is the most frequent pattern; eosinophilic pneumonitis and organizing pneumonia are rarer. Occurrence of bleomycin lung toxicity requires an immediate and often permanent discontinuation. Treatment is based on steroid. Regular clinical and pulmonary function tests monitoring are mandatory for early detection of bleomycin-induced lung toxicity.

Malignancy of Cancers and Synthetic Lethal Interactions Associated With Mutations of Cancer Driver Genes

The mutation status of cancer driver genes may correlate with different degrees of malignancy of cancers. The doubling time and multidrug resistance are 2 phenotypes that reflect the degree of malignancy of cancer cells. Because most of cancer driver genes are hard to target, identification of their synthetic lethal partners might be a viable approach to treatment of the cancers with the relevant mutations.The genome-wide screening for synthetic lethal partners is costly and labor intensive. Thus, a computational approach facilitating identification of candidate genes for a focus synthetic lethal RNAi screening will accelerate novel anticancer drug discovery.We used several publicly available cancer cell lines and tumor tissue genomic data in this study.We compared the doubling time and multidrug resistance between the NCI-60 cell lines with mutations in some cancer driver genes and those without the mutations. We identified some candidate synthetic lethal genes to the cancer driver genes APC, KRAS, BRAF, PIK3CA, and TP53 by comparison of their gene phenotype values in cancer cell lines with the relevant mutations and wild-type background. Further, we experimentally validated some of the synthetic lethal relationships we predicted.We reported that mutations in some cancer driver genes mutations in some cancer driver genes such as APC, KRAS, or PIK3CA might correlate with cancer proliferation or drug resistance. We identified 40, 21, 5, 43, and 18 potential synthetic lethal genes to APC, KRAS, BRAF, PIK3CA, and TP53, respectively. We found that some of the potential synthetic lethal genes show significantly higher expression in the cancers with mutations of their synthetic lethal partners and the wild-type counterparts. Further, our experiments confirmed several synthetic lethal relationships that are novel findings by our methods.We experimentally validated a part of the synthetic lethal relationships we predicted. We plan to perform further experiments to validate the other synthetic lethal relationships predicted by this study.Our computational methods achieve to identify candidate synthetic lethal partners to cancer driver genes for further experimental screening with multiple lines of evidences, and therefore contribute to development of anticancer drugs.

Increased Mutagen Sensitivity and DNA Damage in Pulmonary Arterial Hypertension

RATIONALE

Pulmonary arterial hypertension (PAH) is a serious lung condition characterized by vascular remodeling in the precapillary pulmonary arterioles. We and others have demonstrated chromosomal abnormalities and increased DNA damage in PAH lung vascular cells, but their timing and role in disease pathogenesis is unknown.

OBJECTIVES

We hypothesized that if DNA damage predates PAH, it might be an intrinsic cell property that is present outside the diseased lung.

METHODS

We measured DNA damage, mutagen sensitivity, and reactive oxygen species (ROS) in lung and blood cells from patients with Group 1 PAH, their relatives, and unrelated control subjects.

MEASUREMENTS AND MAIN RESULTS

Baseline DNA damage was significantly elevated in PAH, both in pulmonary artery endothelial cells (P < 0.05) and peripheral blood mononuclear cells (PBMC) (P < 0.001). Remarkably, PBMC from unaffected relatives showed similar increases, indicating this is not related to PAH treatments. ROS levels were also higher (P < 0.01). DNA damage correlated with ROS production and was suppressed by antioxidants (P < 0.001). PBMC from patients and relatives also showed markedly increased sensitivity to two chemotherapeutic drugs, bleomycin and etoposide (P < 0.001). Results were consistent across idiopathic, heritable, and associated PAH groups.

CONCLUSIONS

Levels of baseline and mutagen-induced DNA damage are intrinsically higher in PAH cells. Similar results in PBMC from unaffected relatives suggest this may be a genetically determined trait that predates disease onset and may act as a risk factor contributing to lung vascular remodeling following endothelial cell injury. Further studies are required to fully characterize mutagen sensitivity, which could have important implications for clinical management.

Melatonin reduces oxidative stress and restores mitochondrial function in the liver of rats exposed to chemotherapeutics

This study was undertaken to investigate whether administration of melatonin protects PVB-Induced oxidative and metabolic toxicity in the liver of Wistar rats. Adult male Wistar rats were intraperitoneally injected with either melatonin or PVB (cisplatin, vinblastine, and bleomycin) alone or combination for a period of 9 weeks. A significant increase in lipid peroxidation levels and decrease in catalase and superoxide dismutase activity levels were observed in the liver mitochondria of rats treated with PVB indicating increased oxidative stress. PVB treatment significantly decreased the succinate dehydrogenase activity with a significant increase in lactate dehydrogenase, glucose-6-phosphate dehydrogenase, aspartate aminotransaminase, alanine aminotransaminase, and glutamate dehydrogenase activities indicating deranged hepatic metabolism. Melatonin administration, on the other hand was found to significantly improve PVB-Induced biochemical changes, bringing them closer to the controls. The results from the study provide evidence that treatment with PVB affects hepatic metabolism in rats by inducing oxidative stress followed by decreasing mitochondrial oxidation and also point towards the clinical potential of melatonin as an adjuvant therapy to conventional chemotherapeutic regimens.

Pulmonary and cardiovascular toxicity in long-term testicular cancer survivors

Testicular cancer (TC) is the most common solid organ malignancy among young men at their peak of family life, education, and career. The exceptionally high cure rates are hampered by an increased risk of several treatment-related toxicities that may emerge several years after treatment. In this article, we review the current knowledge regarding pulmonary and cardiovascular toxicity in long-term survivors of TC. Bleomycin pulmonary toxicity is associated with the cumulative bleomycin dose, renal function, age and smoking status and can be avoided by a careful patient evaluation before chemotherapy. Lung function assessments are not routinely recommended for detecting bleomycin pulmonary toxicity. Long-term decreased pulmonary function may also be related to other chemotherapy agents such as cisplatin. Cardiovascular disease represents one of the most serious late effects of cytotoxic treatment in TC survivors and typically appears several years to decades after treatment. The increased risk for cardiovascular disease is probably mediated by a direct vascular damage from cytotoxic treatment that may stimulate the endothelium, possibly ultimately inducing the atherosclerotic process, as well as an indirect cytotoxic effect by increasing the levels of cardiovascular risk factors. Follow-up of these cancer survivors should include recommendations for maintaining a healthy lifestyle to reduce the risk of future cardiovascular events and to avoid declining pulmonary function.

The role of mouse strain differences in the susceptibility to fibrosis: a systematic review

In humans, a number of genetic factors have been linked to the development of fibrosis in a variety of different organs. Seeking a wider understanding of this observation in man is ethically important. There is mounting evidence suggesting that inbred mouse strains with different genetic backgrounds demonstrate variable susceptibility to a fibrotic injury. We performed a systematic review of the literature describing strain and organ specific response to injury in order to determine whether genetic susceptibility plays a role in fibrogenesis. Data were collected from studies that were deemed eligible for analysis based on set inclusion criteria, and findings were assessed in relation to strain of mouse, type of injury and organ of investigation. A total of 44 studies were included covering 21 mouse strains and focusing on fibrosis in the lung, liver, kidney, intestine and heart. There is evidence that mouse strain differences influence susceptibility to fibrosis and this appears to be organ specific. For instance, C57BL/6J mice are resistant to hepatic, renal and cardiac fibrosis but susceptible to pulmonary and intestinal fibrosis. However, BALB/c mice are resistant to pulmonary fibrosis but susceptible to hepatic fibrosis. Few studies have assessed the effect of the same injury stimulus in different organ systems using the same strains of mouse. Such mouse strain studies may prove useful in elucidating the genetic as well as epigenetic factors in humans that could help determine why some people are more susceptible to the development of certain organ specific fibrosis than others.

Revisiting bleomycin from pathophysiology to safe clinical use

Bleomycin is a key component of curative chemotherapy regimens employed in the treatment of curable cancers, such as Hodgkin lymphoma (HL) and testicular germ-cell tumours (GCT), yet its use may cause bleomycin-induced lung injury (BILI), which is associated with significant morbidity and a mortality rate of 1-3%. Diagnosis of BILI is one of exclusion and physicians involved in the care of HL and GCT patients should be alerted. Pharmacogenomic studies could contribute towards the identification of molecular predictors of bleomycin toxicity on the aim to optimize individual use of bleomycin. We review all existing data on bleomycin's most recent integrated chemical biology, molecular pharmacology and mature clinical data and provide guidelines for its safe clinical use.

Variation in dicer gene is associated with increased survival in T-cell lymphoma

Dicer, an endonuclease in RNase III family, is essential for the RNA interference (RNAi) pathway. Aberrant expression of Dicer has been shown in various cancers including some subtypes of T cell lymphoma (TCL), which influences patient prognosis. A single-nucleotide polymorphism (SNP) rs3742330A>G has been identified in the Dicer gene, located in the 3′ untranslated region (3′ UTR) that is important for mRNA transcript stability. We investigated whether rs3742330 is associated with the survival in 163 TCL patients. Significant association between Dicer rs3742330 and TCL survival were found. Patients carrying the GG genotype (n = 12) had a significantly increased overall survival (OS) compared with those carrying the GA and AA genotypes (n = 70 and n = 81, respectively; p = 0.031). Moreover, the significant association was maintained for patients with mature T type (n = 134; p = 0.026). In multivariate Cox-regression analysis, rs3742330 proved to be an independent predictor for OS, together with the commonly used International Prognostic Index (IPI) and BAFF rs9514828, another SNP we have previously reported to be associated with TCL survival, with hazard ratios (HRs) for patient death rate of 8.956 (95% CI, 1.210 to 66.318; p = 0.032) for the GA genotype and 10.145 (95% CI, 1.371 to 75.084; p = 0.023) for the AA genotype. Furthermore, we observed cumulative effects of Dicer rs3742330 and BAFF rs9514828 on TCL survival. Compared with patients carrying zero unfavorable genotype, those carrying one and two unfavorable genotypes had an increased risk of death with a HR of 7.104 (95% CI, 0.969–53.086; p = 0.054) and 14.932 (95% CI, 1.950–114.354; p = 0.009), respectively, with a significant dose-response trend (p_trend  = 0.004). In conclusion, Dicer rs3742330 is associated with TCL survival, suggesting that genetic variation might play a role in predicting prognosis of TCL patients.

Cancer Genomics: Technology, Discovery, and Translation

In recent years, the increasing awareness that somatic mutations and other genetic aberrations drive human malignancies has led us within reach of personalized cancer medicine (PCM). The implementation of PCM is based on the following premises: genetic aberrations exist in human malignancies; a subset of these aberrations drive oncogenesis and tumor biology; these aberrations are actionable (defined as having the potential to affect management recommendations based on diagnostic, prognostic, and/or predictive implications); and there are highly specific anticancer agents available that effectively modulate these targets. This article highlights the technology underlying cancer genomics and examines the early results of genome sequencing and the challenges met in the discovery of new genetic aberrations. Finally, drawing from experiences gained in a feasibility study of somatic mutation genotyping and targeted exome sequencing led by Princess Margaret Hospital–University Health Network and the Ontario Institute for Cancer Research, the processes, challenges, and issues involved in the translation of cancer genomics to the clinic are discussed.

Chemotherapy refractory testicular germ cell tumor is associated with a variant in Armadillo Repeat gene deleted in Velco-Cardio-Facial syndrome (ARVCF)

INTRODUCTION

There is evidence that inherited genetic variation affects both testicular germ cell tumor (TGCT) treatment outcome and risks of late-complications arising from cisplatin-based chemotherapy. Using a candidate gene approach, we examined associations of three genes involved in the cisplatin metabolism pathway, GSTP1, COMT, and TPMT, with TGCT outcome and cisplatin-induced neurotoxicity.

MATERIALS AND METHODS

Our study population includes a subset of patients (n = 137) from a genome-wide association study at the University of Pennsylvania that evaluates inherited genetic susceptibility to TGCT. All patients in our study had at least one course of cisplatin-based chemotherapy with at least 1 year of follow-up. A total of 90 markers in GSTP1, COMT, and TPMT and their adjacent genomic regions (±20 kb) were analyzed for associations with refractory TGCT after first course of chemotherapy, progression-free survival (PFS), overall survival (OS), peripheral neuropathy, and ototoxicity.

RESULTS

After adjustment for multiple comparisons, one Single nucleotide polymorphism (SNP), rs2073743, in the flanking region (±20 kb) of COMT was associated with refractory TGCT after initial chemotherapy. This SNP lies within the intron region of the Armadillo Repeat gene deleted in Velco-Cardio-Facial syndrome (ARVCF). The G allele of rs2073743 predisposed patients to refractory disease with a relative risk of 2.6 (95% CI 1.1, 6.3; P = 0.03). Assuming recessive inheritance, patients with the GG genotype had 22.7 times higher risk (95% CI 3.3, 155.8; P = 0.04) of developing refractory disease when compared to those with the GC or CC genotypes. We found no association of our candidate genes with peripheral neuropathy, ototoxicity, PFS and OS.

DISCUSSION

This is the first study to suggest that germline genetic variants of ARVCF may affect TGCT outcome. The result of this study is hypothesis generating and should be validated in future studies.

Identification of the bleomycin hydrolase gene as a methylated tumor suppressor gene in hepatocellular carcinoma using a novel triple-combination array method

In the present study, we sought to identify novel suppressor genes of hepatocellular carcinoma (HCC) using our newly designed triple-combination array. Using this method, the bleomycin hydrolase gene (BLMH) was detected as a candidate suppressor gene. We found that 28 of 48 (58.3%) tumor tissues showed BLMH promoter hypermethylation, and its expression level was significantly reduced in tumor tissues (P=0.001). The present study suggests that our new method can detect novel genes of interest and that BLMH is a suppressor gene in HCC.

Part 2: pharmacogenetic variability in drug transport and phase I anticancer drug metabolism

Equivalent drug doses in anticancer chemotherapy may lead to wide interpatient variability in drug response reflected by differences in treatment response or in severity of adverse drug reactions. Differences in the pharmacokinetic (PK) and pharmacodynamic (PD) behavior of a drug contribute to variation in treatment outcome among patients. An important factor responsible for this variability is genetic polymorphism in genes that are involved in PK/PD processes, including drug transporters, phase I and II metabolizing enzymes, and drug targets, and other genes that interfere with drug response. In order to achieve personalized pharmacotherapy, drug dosing and treatment selection based on genotype might help to increase treatment efficacy while reducing unnecessary toxicity. We present a series of four reviews about pharmacogenetic variability in anticancer drug treatment. This is the second review in the series and is focused on genetic variability in genes encoding drug transporters (ABCB1 and ABCG2) and phase I drug-metabolizing enzymes (CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A4, CYP3A5, DPYD, CDA and BLMH) and their associations with anticancer drug treatment outcome. Based on the literature reviewed, opportunities for patient-tailored anticancer therapy are presented.

Prognostic impact of bleomycin-induced pneumonitis on the outcome of Hodgkin's lymphoma

Bleomycin-induced pneumonitis (BIP) has been well described in Hodgkin's lymphoma (HL) patients. The impact of BIP on patients uniformly treated with adriamycin, bleomycin, vinblastine, and dacarbazine (ABVD) is not clear; previous studies have included patients treated with both ABVD and hybrid regimens. We reviewed our experience with BIP in HL to better understand the impact of BIP on overall survival. One hundred and eighty four consecutive patients who were treated with ABVD for newly diagnosed HL were eligible for retrospective review. BIP was defined by the presence of pulmonary symptoms, bilateral interstitial infiltrates on chest X-ray, computed tomography or presence of lung fibrosis on transbronchial lung biopsy, and the absence of infection. Patients were required to meet all three criteria to be included in the BIP group. BIP was observed in 28 patients (15%). A low albumin level and the use of colony granulocyte stimulating factor were associated with a higher risk of developing BIP. Age, smoking history, and underlying lung function were not predictive of BIP. Importantly, patients with BIP had similar rates of 5-year overall survival compared to unaffected patients. There were no deaths from BIP. Omission of bleomycin from subsequent treatment did not adversely affect the outcomes.

Testicular cancer survivorship: research strategies and recommendations

Testicular cancer represents the most curable solid tumor, with a 10-year survival rate of more than 95%. Given the young average age at diagnosis, it is estimated that effective treatment approaches, in particular, platinum-based chemotherapy, have resulted in an average gain of several decades of life. This success, however, is offset by the emergence of considerable long-term morbidity, including second malignant neoplasms, cardiovascular disease, neurotoxicity, nephrotoxicity, pulmonary toxicity, hypogonadism, decreased fertility, and psychosocial problems. Data on underlying genetic or molecular factors that might identify those patients at highest risk for late sequelae are sparse. Genome-wide association studies and other translational molecular approaches now provide opportunities to identify testicular cancer survivors at greatest risk for therapy-related complications to develop evidence-based long-term follow-up guidelines and interventional strategies. We review research priorities identified during an international workshop devoted to testicular cancer survivors. Recommendations include 1) institution of lifelong follow-up of testicular cancer survivors within a large cohort setting to ascertain risks of emerging toxicities and the evolution of known late sequelae, 2) development of comprehensive risk prediction models that include treatment factors and genetic modifiers of late sequelae, 3) elucidation of the effect(s) of decades-long exposure to low serum levels of platinum, 4) assessment of the overall burden of medical and psychosocial morbidity, and 5) the eventual formulation of evidence-based long-term follow-up guidelines and interventions. Just as testicular cancer once served as the paradigm of a curable malignancy, comprehensive follow-up studies of testicular cancer survivors can pioneer new methodologies in survivorship research for all adult-onset cancer.

Males with familial idiopathic scoliosis: a distinct phenotypic subgroup

STUDY DESIGN

Statistical analysis of genomic screening and fine mapping data.

OBJECTIVE

The goals of this study were to analyze a region on chromosome 17 and to identify specific genetic determinants within this region linked to familial idiopathic scoliosis (FIS) in a subgroup of families in which affected males have undergone surgery.

SUMMARY OF BACKGROUND DATA

The high prevalence and variability of FIS is indicative of genetic heterogeneity. To localize genes related to scoliosis, identification of groups of families with common clinical characteristics is a strategy that reduces genetic heterogeneity. Two independent studies have implicated a region on chromosome 17 as related to FIS.

METHODS

With approval of the Institutional Review Board, the initial study population consisted of 202 families (1198 individuals), each of which had 2 or more affected individuals; 17 of those families had an affected male who had surgery. Individuals underwent genomic screening and subsequent fine mapping. Results were obtained using model-independent linkage analysis, with scoliosis set as a qualitative and as a quantitative trait, as implemented in SIBPAL (S.A.G.E., v4.5). The level of significance was set at P < or = 0.05.

RESULTS

The initial study population had significant results at markers d17s975 and d17s2196. Analyses of a subgroup of families with males having undergone surgery using a customized single nucleotide polymorphism panel resulted in increased significance of this region.

CONCLUSION

The data confirm a previously reported genetic locus on chromosome 17 as statistically significant in the etiology of FIS within a subgroup of families in which an affected male had spinal surgery.

[Chemo- and radiotherapy of germ cell testicular cancer in the literature]

The study reviews the incidence, histologic types and prognostic factors of testicular cancer. The measurement of tumor-marker levels before castration determine the further activity regarding the data of imagings. The authors explain the treatment of seminoma and non-seminoma by stages. Carboplatin monotherapy is equivalent to the irradiation in early seminoma cases. Nowadays applied second and third line chemotherapies are reviewed. It is necessary to take into consideration not only the remission rate but also the late toxicity during the complex treatment of testicular germ cell cancer.