Maternal Exposure to Cigarette Smoke during Pregnancy and Testicular Cancer in Offspring: A Systematic Review and Meta-Analysis

Background: Maternal exposure to cigarette smoke in pregnancy may play a role in the development of testicular cancer in offspring. An updated and comprehensive systematic review of the available evidence is needed. Objective: To identify and evaluate current evidence on maternal exposure to cigarette smoke during pregnancy and testicular cancer in offspring. Methods: A systematic search of English peer-reviewed original literature in PubMed through a block search approach. Publications were considered if assessing maternal exposure to cigarette smoke and the risk of testicular cancer in offspring. Results: Among the 636 identified records, 14 publications were eligible for review and 10 for meta-analysis. Quality assessment of the publications was conducted. Most included publications were case-control studies (n = 11, 79%), while the remaining were ecological studies (n = 3, 21%). Completeness of reporting was high, but more than half were considered subject to potential bias. The trend synthesis showed that half (n = 7) of the included publications demonstrated a higher risk of testicular cancer in the sons of mothers exposed to cigarette smoke during pregnancy. The meta-analysis generated an overall summary risk estimate of 1.00 (95% CI: 0.88; 1.15) (n = 10 publications), with a lower risk for seminoma (0.79, 95% CI: 0.59; 1.04) and nonseminoma (0.96, 95% CI: 0.74; 1.26) (n = 4 publications). Conclusions: This systematic review did not provide evidence of an association between maternal exposure to cigarette smoke and risk of testicular cancer in offspring. An overall positive trend was suggested, but it had low statistical precision. The methodological limitations across publications encourage further research based on valid exposure data.

Temporal decline of sperm concentration: role of endocrine disruptors

INTRODUCTION

Male infertility is a widespread disease with an etiology that is not always clear. A number of studies have reported a decrease in sperm production in the last forty years. Although the reasons are still undefined, the change in environmental conditions and the higher exposure to endocrine-disrupting chemicals (EDCs), namely bisphenol A, phthalates, polychlorinated biphenyls, polybrominated diphenyl esters, dichlorodiphenyl-dichloroethylene, pesticides, and herbicides, organophosphates, and heavy metals, starting from prenatal life may represent a possible factor justifying the temporal decline in sperm count.

AIM

The aim of this study is to provide a comprehensive description of the effects of the exposure to EDCs on testicular development, spermatogenesis, the prevalence of malformations of the male genital tract (cryptorchidism, testicular dysgenesis, and hypospadias), testicular tumor, and the mechanisms of testicular EDC-mediated damage.

NARRATIVE REVIEW

Animal studies confirm the deleterious impact of EDCs on the male reproductive apparatus. EDCs can compromise male fertility by binding to hormone receptors, dysregulating the expression of receptors, disrupting steroidogenesis and hormonal metabolism, and altering the epigenetic mechanisms. In humans, exposure to EDCs has been associated with poor semen quality, increased sperm DNA fragmentation, increased gonadotropin levels, a slightly increased risk of structural abnormalities of the genital apparatus, such as cryptorchidism and hypospadias, and development of testicular tumor. Finally, maternal exposure to EDCs seems to predispose to the risk of developing testicular tumors.

CONCLUSION

EDCs negatively impact the testicular function, as suggested by evidence in both experimental animals and humans. A prenatal and postnatal increase to EDC exposure compared to the past may likely represent one of the factors leading to the temporal decline in sperm counts.

Altered DNA methylation in estrogen-responsive repetitive sequences of spermatozoa of infertile men with shortened anogenital distance

BACKGROUND

It has been suggested that antenatal exposure to environmental endocrine disruptors is responsible for adverse trends in male reproductive health, including male infertility, impaired semen quality, cryptorchidism and testicular cancer, a condition known as testicular dysgenesis syndrome. Anogenital distance (AGD) is an anthropomorphic measure of antenatal exposure to endocrine disruptors, with higher exposure levels leading to shortened AGD. We hypothesized that exposure to endocrine disruptors could lead to changes in DNA methylation during early embryonic development, which could then persist in the sperm of infertile men with shortened AGD.

RESULTS

Using fluorescence activated cell sorting based on staining with either YO-PRO-1 (YOPRO) or chromomycin-3 (CMA3), we isolated four sperm fractions from eleven infertile men with short AGD and ten healthy semen donors. We examined DNA methylation in these sorted spermatozoa using reduced representation bisulfite sequencing. We found that fractions of spermatozoa from infertile men stained with CMA3 or YOPRO were more likely to contain transposable elements harboring an estrogen receptor response element (ERE). Abnormal sperm (as judged by high CMA3 or YOPRO staining) from infertile men shows substantial hypomethylation in estrogenic Alu sequences. Conversely, normal sperm fractions (as judged by low CMA3 or YO-PRO-1 staining) of either healthy donors or infertile patients were more likely to contain hypermethylated Alu sequences with ERE.

CONCLUSIONS

Shortened AGD, as related to previous exposure to endocrine disruptors, and male infertility are accompanied by increased presence of hormonal response elements in the differentially methylated regulatory sequences of the genome of sperm fractions characterized by chromatin decondensation and apoptosis.

Environmental factors in declining human fertility

A severe decline in child births has occurred over the past half century, which will lead to considerable population declines, particularly in industrialized regions. A crucial question is whether this decline can be explained by economic and behavioural factors alone, as suggested by demographic reports, or to what degree biological factors are also involved. Here, we discuss data suggesting that human reproductive health is deteriorating in industrialized regions. Widespread infertility and the need for assisted reproduction due to poor semen quality and/or oocyte failure are now major health issues. Other indicators of declining reproductive health include a worldwide increasing incidence in testicular cancer among young men and alterations in twinning frequency. There is also evidence of a parallel decline in rates of legal abortions, revealing a deterioration in total conception rates. Subtle alterations in fertility rates were already visible around 1900, and most industrialized regions now have rates below levels required to sustain their populations. We hypothesize that these reproductive health problems are partially linked to increasing human exposures to chemicals originating directly or indirectly from fossil fuels. If the current infertility epidemic is indeed linked to such exposures, decisive regulatory action underpinned by unconventional, interdisciplinary research collaborations will be needed to reverse the trends.

Long-term residential exposure to air pollution and risk of testicular cancer in Denmark: A population-based case-control study

BACKGROUND

The incidence rate risk of testicular cancer has increased over the last four decades, and most significant increase has been among Caucasian men in Nordic countries. Second-generation immigrant studies indicate a significant role of environmental exposure in testicular cancer.

METHODS

We conducted a nationwide register-based case-control study, including 6,390 testicular cancer cases registered in the Danish Cancer Registry between 1989 and 2014. Up to four age-matched controls for each case (n=18,997) were randomly selected from Civil Registration System. Ambient air pollution levels were estimated at addresses of cases and controls with a state-of-the-art air pollution modeling system.

RESULTS

We mostly found ORs close to 1.00 and with 95% confidence intervals (CI) spanning 1.00. Exposure during the year preceding birth was associated with ORs for NO2 of 0.87 (95%CI: 0.77-0.97) per 10 µg/m3 and for organic carbon of 0.84 (95%CI: 0.72-0.98) per 1 µg/m3. Exposure during the first 10 years of life was associated with ORs for organic carbon of 0.79 (95%CI: 0.67-0.93) per 1 µg/m3, for O3 of 1.20 (95%CI: 1.07-1.34) per 10 µg/m3 and for secondary inorganic aerosols of 1.07 (95%CI: 1.00-1.15) per 1 µg/m3.

CONCLUSIONS

Early-life exposure to NO2 and OC was associated with lower risk for testicular cancer whereas early-life exposure to O3 and SIA was associated with higher risk.

IMPACT

We report both positive and negative associations between ambient air pollutants and risk of testicular, dependent on pollutant, exposure time window and age at diagnosis. This is the first study to investigate such associations.

Trends in testicular germ cell tumors among native black African men do not mirror those of African Americans: multi-institutional data from South Africa

Background

Testicular germ cell tumor (TGCT) is most frequently diagnosed in young males and its etiology remains poorly understood. Cases of newly diagnosed TGCT have been rising in the United States and incidence among African Americans (AA) has increased nearly 40%. Incidence of TGCT in native black African (BA) males, conversely, has remained low. We sought to determine the racial identification of patients diagnosed with TGCT in Cape Town, South Africa. We hypothesize that the rise in TGCT among AA males is distinct from that of BA males in South Africa.

Methods

A retrospective review involving two tertiary care centres in the Western Cape was performed. Data were extracted for males > 13 years of age diagnosed with TGCT from January 1, 2000 to June 30, 2015. Racial status was self-declared and included BA, Caucasian, Mixed Ancestry (MA), and Asian. Patients were identified from combined Urology–Oncology clinic logs at both institutions, as well as from pathology records at the National Health Laboratory Service indicating any form of testicular cancer.

Results

225 patients were identified. 97% of cases involved males identified as MA (130) or Caucasian (88). Only 2% of the study population identified as BA, with complete absence of self-identifying BA males for several years within the queried interval. Among males diagnosed with TGCT, the percentage self-identifying as Caucasian increased over time (R2 0.92).

Conclusions

Males diagnosed with TGCT in the Western Cape predominantly self-identify as MA or Caucasian. Exceedingly few cases are attributed to BA, and even less to Asian males. The trend in racial distribution suggests that the increasing incidence reported for AAs may be due to interracial gene exchange, environmental factors, or a combination thereof.

Proximity to endocrine-disrupting pesticides and risk of testicular germ cell tumors (TGCT) among adolescents: A population-based case-control study in California

BACKGROUND

The incidence of testicular germ cell tumors (TGCT) is increasing steadily in the United States, particularly among Latinos. TGCT is thought to be initiated in utero and exposure to endocrine-disrupting chemicals, suspected contributors to TGCT pathogenesis, during this critical developmental period may contribute to the rise.

OBJECTIVES

To assess the relationship between fetal exposure to agricultural endocrine-disrupting pesticides (EDPs) and TGCT risk among adolescents in a diverse population in California.

METHODS

We conducted a registry-based case-control study of TGCT. Cases, diagnosed between 1997 and 2011, were 15-19 years of age (n = 381). Controls were matched on birth year and race/ethnicity (n = 762). Quantities (kilograms) of 33 pesticides applied within 3 km and 1 km radii of each individual's address before birth were estimated using the Pesticide Use Reporting database. Odds ratios (OR), 95% confidence intervals (CI), and population attributable risk (PAR) were calculated for each EDP (using log-2 transformed values). Risk models considered race/ethnicity, birth year, and neighborhood socioeconomic status.

RESULTS

A doubling of nearby acephate applications (3 km and 1 km radii) and malathion applications (1 km radius) was associated with increased risks of TGCT among Latinos only (OR = 1.09; 95% CI:1.01-1.17; 1.30; 95% CI:1.08-1.57, and 1.19; 95% CI:1.01-1.39, respectively), whereas application of carbaryl within a 3 km radius increased TGCT risk in non-Latinos only (OR = 1.14, 95% CI:1.01-1.28). We estimate that acephate was associated with approximately 10% of the TGCT PAR, malathion with 3% and carbaryl with 1%.

CONCLUSIONS

TGCT among adolescents in California was associated with prenatal residential proximity to acephate and malathion among Latinos, and with carbaryl among non-Latinos. These results suggest that the rise in TGCT risk among Latinos may be associated with exposure to these pesticides.

Endocrine Disrupting Chemicals and Risk of Testicular Cancer: A Systematic Review and Meta-analysis

The incidence of many hormone-dependent diseases, including testicular cancer, has sharply increased in all high-income countries during the 20th century. This is not fully explained by established risk factors. Concurrent, increasing exposure to antiandrogenic environmental endocrine disrupting chemicals (EDCs) in fetal life may partially explain this trend. This systematic review assessed available evidence regarding the association between environmental EDC exposure and risk of testicular cancer (seminomas and nonseminomas). Following PRISMA guidelines, a search of English peer-reviewed literature published prior to December 14, 2020 in the databases PubMed and Embase® was performed. Among the 279 identified records, 19 were eligible for quality assessment and 10 for further meta-analysis. The completeness of reporting was high across papers, but over 50% were considered subject to potential risk of bias. Mean age at diagnosis was 31.9 years. None considered effects of EDC multipollutant mixtures. The meta-analyses showed that maternal exposure to combined EDCs was associated with a higher risk of testicular cancer in male offspring [summary risk ratios: 2.16, (95% CI:1.78-2.62), 1.93 (95% CI:1.49-2.48), and 2.78 (95% CI:2.27-3.41) for all, seminoma, and nonseminoma, respectively]. Similarly, high maternal exposures to grouped organochlorines and organohalogens were associated with higher risk of seminoma and nonseminoma in the offspring. Summary estimates related to postnatal adult male EDC exposures were inconsistent. Maternal, but not postnatal adult male, EDC exposures were consistently associated with a higher risk of testicular cancer, particularly risk of nonseminomas. However, the quality of studies was mixed, and considering the fields complexity, more prospective studies of prenatal EDC multipollutant mixture exposures and testicular cancer are needed.

A population-based study of testicular cancer risk among children and young adults from Norway and Utah, USA

Similar family-based cancer and genealogy data from Norway and Utah allowed comparisons of the incidence of testicular cancer (TC), and exploration of the role of Scandinavian ancestry and family history of TC in TC risk. Our study utilizes data from the Utah Population Database and Norwegian Population Registers. All males born during 1951-2015 were followed for TC until the age of 29 years. A total of 1,974,287 and 832,836 males were born in Norway and Utah, respectively, of whom 2,686 individuals were diagnosed with TC in Norway and 531 in Utah. The incidence per year of TC in Norway (10.6) was twice that observed in Utah (5.1) for males born in the last period (1980-1984). The incidence rates of TC in Utah did not differ according to the presence or absence of Scandinavian ancestry (p = 0.669). Having a brother diagnosed with TC was a strong risk factor for TC among children born in Norway and Utah, with HR = 9.87 (95% CI 5.68-17.16) and 6.02 (95% CI 4.80-7.55), respectively; with even higher HR observed among the subset of children in Utah with Scandinavian ancestry (HR = 12.30, 95% CI 6.78-22.31). A clear difference in TC incidence among individuals born in Norway and descendants of Scandinavian people born in Utah was observed. These differences in TC rates point to the possibility of environmental influence. Family history of TC is a strong risk factor for developing TC in both populations.

Male Reproductive Disorders and Fertility Trends: Influences of Environment and Genetic Susceptibility

It is predicted that Japan and European Union will soon experience appreciable decreases in their populations due to persistently low total fertility rates (TFR) below replacement level (2.1 child per woman). In the United States, where TFR has also declined, there are ethnic differences. Caucasians have rates below replacement, while TFRs among African-Americans and Hispanics are higher. We review possible links between TFR and trends in a range of male reproductive problems, including testicular cancer, disorders of sex development, cryptorchidism, hypospadias, low testosterone levels, poor semen quality, childlessness, changed sex ratio, and increasing demand for assisted reproductive techniques. We present evidence that several adult male reproductive problems arise in utero and are signs of testicular dysgenesis syndrome (TDS). Although TDS might result from genetic mutations, recent evidence suggests that it most often is related to environmental exposures of the fetal testis. However, environmental factors can also affect the adult endocrine system. Based on our review of genetic and environmental factors, we conclude that environmental exposures arising from modern lifestyle, rather than genetics, are the most important factors in the observed trends. These environmental factors might act either directly or via epigenetic mechanisms. In the latter case, the effects of exposures might have an impact for several generations post-exposure. In conclusion, there is an urgent need to prioritize research in reproductive physiology and pathophysiology, particularly in highly industrialized countries facing decreasing populations. We highlight a number of topics that need attention by researchers in human physiology, pathophysiology, environmental health sciences, and demography.

Polygenic susceptibility to testicular cancer: implications for personalised health care

BACKGROUND

The increasing incidence of testicular germ cell tumour (TGCT) combined with its strong heritable basis suggests that stratified screening for the early detection of TGCT may be clinically useful. We modelled the efficiency of such a personalised screening approach, based on genetic risk profiling in combination with other diagnostic tools.

METHODS

We compared the number of cases potentially detectable in the population under a number of screening models. The polygenic risk scoring (PRS) model was assumed to have a log-normal relative risk distribution across the 19 currently known TGCT susceptibility variants. The diagnostic performance of testicular biopsy and non-invasive semen analysis was also assessed, within a simulated combined screening programme.

RESULTS

The area under the curve for the TGCT PRS model was 0.72 with individuals in the top 1% of the PRS having a nine-fold increased TGCT risk compared with the population median. Results from population-screening simulations only achieved a maximal positive predictive value (PPV) of 60%, highlighting broader clinical factors that challenge such strategies, not least the rare nature of TGCT. In terms of future improvements, heritability estimates suggest that a significant number of additional genetic risk factors for TGCT remain to be discovered, identification of which would potentially yield improvement of the PPV to 80-90%.

CONCLUSIONS

While personalised screening models may offer enhanced TGCT risk discrimination, presently the case for population-level testing is not compelling. However, future advances, such as more routine generation of whole genome data is likely to alter the landscape. More targeted screening programs may plausibly then offer clinical benefit, particularly given the significant survivorship issues associated with the successful treatment of TGCT.

Studying the impact of early life exposures to pesticides on the risk of testicular germ cell tumors during adulthood (TESTIS project): study protocol

BACKGROUND

The incidence of testicular germ cell tumors (TGCT), the most common cancer in men aged 15 to 45 years, has doubled over the last 30 years in developed countries. Reasons remain unclear but a role of environmental factors, especially during critical periods of development, is strongly suspected. Reliable data on environmental exposure during this critical time period are sparse. Little is known on whether it could be a combined effect of early and later-life exposures.

METHODS/DESIGN

Our research aims to study the association between TGCT risk and pesticide exposures (domestic, occupational and environmental) during critical time periods of development and combined early and later-life exposures. The study design, developed during a 2-year pilot study, is a multicenter case-control study of 500 cases (ascertained through histology) and 1000 fertile/fecund controls recruited through 21 French 'Centres d'Etude et de Conservation des Œufs et de Sperme humain' (CECOS). Trained professional interviewers interview the subjects and their mothers by phone. Using a geographic information system developed and tested for application in this study design, environmental pesticides exposure assessment is based on life-time residential history. Occupational pesticides exposures are assessed by an industrial hygienist based on parents' occupations and tasks. Exposures during the prenatal period, early childhood and puberty are focused. A blood sample is collected from each participant to assess genetic polymorphisms known to be associated with TGCT risk, as well as to explore gene-environment interactions.

DISCUSSION

The results of our study will contribute to better understanding the causes of TGCT and the rapid increase of its incidence. We explore the effect of combined early and later-life pesticides exposure from multiple sources, as well as potential gene-environment interactions that have until now been rarely studied for TGCT. Our design allows future pooled studies and the bio-bank allows additional genetic or toxicological analyses.

[Testicular germ cell tumours and early exposures to pesticides: The TESTEPERA pilot study]

Testicular germ cell tumors (TGCT) represent the most frequent cancer in men aged between 15 and 45 years. Current hypotheses are focusing on environmental exposures occurring during prenatal periods. However, very few studies have explored intra-uterine environmental exposure related to TGCT. TESTEPERA is a pilot case-control study aiming to determine the effectiveness of different recruitment approaches in the French context and to verify our ability to collect relevant data on their prenatal periods. Between 2011 and 2012, 150 male subjects were contacted in the Rhône-Alpes region (58 cases from a cancer center and 92 controls from a regional maternity). Participation rate varied from 33% for cases diagnosed in 2008 vs 68% for cases diagnosed in 2010. Participation rate of controls varied depending on modalities of contact (13% for face-to-face recruitment; 0% for contact by phone only; 50% for face-to-face contact with phone reminder). Data collection allowed precise job identification and geolocation of subjects' addresses. Precision of geolocation was dependent upon the level of urbanization (p < 0.001) but not on the time period (p = 0.52). Our results support the feasibility of a case-control study focusing on the relation between TGCT and environmental pesticide exposures during early and later life.

Occupational and environmental exposures associated with testicular germ cell tumours: systematic review of prenatal and life-long exposures

Background

Testicular germ cell tumours (TGCT) are the most common cancers in men aged between 15 and 44 years and the incidence has increased steeply over the past 30 years. The rapid increase in the incidence, the spatial variation and the evolution of incidence in migrants suggest that environmental risk factors play a role in TGCT aetiology. The purpose of our review is to summarise the current state of knowledge on occupational and environmental factors thought to be associated with TGCT.

Methods

A systematic literature search of PubMed. All selected articles were quality appraised by two independent researchers using the ‘Newcastle-Ottawa Quality Assessment Scale’.

Results

After exclusion of duplicate reports, 72 relevant articles were selected; 65 assessed exposure in adulthood, 7 assessed parental exposures and 2 assessed both. Associations with occupation was reported for agricultural workers, construction workers, firemen, policemen, military personnel, as well as workers in paper, plastic or metal industries. Electromagnetic fields, PCBs and pesticides were also suggested. However, results were inconsistent and studies showing positive associations tended to had lower quality ranking using the assessment scale (p=0.02).

Discussion

Current evidence does not allow concluding on existence of any clear association between TGCT and adulthood occupational or environmental exposure. The limitations of the studies may partly explain the inconsistencies observed. The lack of association with adulthood exposure is in line with current hypotheses supporting the prenatal origin of TGCT. Future research should focus on prenatal or early life exposure, as well as combined effect of prenatal and later life exposure. National and international collaborative studies should allow for more adequately powered epidemiological studies. More sophisticated methods for assessing exposure as well as evaluating gene–environment interactions will be necessary to establish clear conclusion.

Epigenetic mechanisms in the actions of endocrine-disrupting chemicals: gonadal effects and role in female reproduction

There is a heightened interest and concern among scientists, clinicians and regulatory agencies as well as the general public, regarding the effects of environmental endocrine-disrupting chemicals (EDCs). In this review, we identify the main epigenetic mechanisms and describe key ovarian processes that are vulnerable to the epigenetic actions of EDCs. We also provide an overview of the human epidemiological evidence documenting the detrimental effects of several common environmental EDCs on female reproduction. We then focus on experimental evidence demonstrating the epigenetic effects of these EDCs in the ovary and female reproductive system, with an emphasis on methoxychlor, an organochlorine pesticide. We conclude the review by describing several critical issues in studying epigenetic effects of EDCs in the ovary, including transgenerational epigenetic effects.

Le cancer du testicule : facteurs de risque génétiques et environnementaux

L'incidence du cancer du testicule (CT), qui est inégale d'une région à l'autre, progresse dans la plupart des pays y compris la France. L'origine la plus probable du CT est la non différenciation de cellules germinales souches pendant la vie fœtale. Ces cellules, maintenues dans un état immature, pourraient proliférer pour former une tumeur après la puberté. La fréquence de son association avec une cryptorchidie ou une infertilité a conduit à formuler l'hypothèse que le CT pouvait être un des constituants du syndrome de dysgénésie testiculaire. Le rôle des facteurs génétiques est suggéré par la fréquence de cas familiaux de CT mais aucun gène clairement responsable du cancer n'a été identifié jusqu'à présent. Parmi les nombreux gènes étudiés, ce sont ceux contrôlant la voie KITLG/KIT, qui participe à la régulation de la prolifération et de la fonction des cellules germinales primordiales, qui semblent jouer le rôle principal. Les études faites sur des populations migrantes et les jumeaux suggèrent par ailleurs que des facteurs environnementaux pourraient jouer un rôle essentiel dans la genèse du CT. Des dérégulations hormonales pendant la vie fœtale ou la puberté pourraient notamment favoriser le développement de CT. Cependant, l'exposition à des substances exogènes agissant comme des perturbateurs endocriniens est encore à démontrer.

Testicular cancer: a narrative review of the role of socioeconomic position from risk to survivorship

BACKGROUND

Testicular cancer (TC) is one of the most curable cancers. Given survival rates of close to 100% with appropriate therapy, ensuring proper treatment is essential. We reviewed and summarized the literature on the association of socioeconomic position (SEP) along the cancer control spectrum from risk factors to survivorship.

METHODS

We searched PubMed from 1966 to 2011 using the following terms: testicular cancer, testicular neoplasm, poverty, and socioeconomic factors, retrieving 119 papers. After excluding papers for the non-English (10) language and non-relevance (46), we reviewed 63 papers. We abstracted information on socioeconomic position (SEP), including occupation, education, income, and combinations of the 3. Five areas were examined: risk factors, diagnosis, treatment, survival, and survivorship.

RESULTS

Most studies examined area-based measures, not individual measures of SEP. The majority of studies found an increased risk of developing TC with high SEP though recent papers have indicated increased risk in low-income populations. Regarding diagnosis, recent papers have indicated that lower levels of education and SEP are risk factors for later-stage TC diagnosis and hence higher TC mortality. For treatment, 1 study that examined the use of radiation therapy (RT) in stage I seminoma reported that living in a county with lower educational attainment led to lower use of RT. For survival (mortality), several studies found that men living in lower SEP geographic areas experience lower survival and higher mortality.

CONCLUSION

The strongest evidence for SEP impact on testicular germ cell tumor (TGCT) was found for the risk of developing cancer as well as survival. The association of SEP with TGCT risk appears to have changed over the last decade. Given the highly curable nature of TGCT, more research is needed to understand how SEP impacts diagnosis and treatment for TGCT and to design interventions to address disparities in TGCT outcomes and SEP.

[Teratozoospermia, myth or reality? A 10-years retrospective study on 101404 consecutive sperm samples]

OBJECTIVES

Several studies have reported a time-related decline in semen quality. In this context, 101,404 spermograms-spermocytograms performed in a single andrology laboratory from January 2000 to December 2009 were investigated retrospectively. Variations of sperm parameters were analyzed over the years.

PATIENTS AND METHODS

For each semen sample, age at semen collection, duration of sexual abstinence, volume of seminal fluid, pH, concentration of spermatozoa, percentages of overall motile and progressive motile sperm, percentage of morphologically abnormal spermatozoa (according to David's classification) and amplitude of lateral head displacement (ALH) were analyzed. For each parameter, the mean value per year was determined. To examine trends over time the statistical tests used were analyses of variance and correlation studies.

RESULTS

Data showed an increasing age of patients from 36.5 years in 2000 to 37.2 years in 2009. The semen concentration was 63.5 millions/mL in 2000 and 63.6 millions/mL in 2009 with a slight fall from 2001 to 2008. The vitality continuously increased from 67.8% in 2000 to 73.5% in 2009 as well as the overall motility (from 37.7% to 39.2%) and the progressive motility (from 34.6% to 36.2%). The percentage of morphologically abnormal spermatozoa continuously increased from 64.5% to 84.2% (r=0.43, P<0.001).

DISCUSSION AND CONCLUSION

Contrary to a variety of works, our very large study of semen analysis did not show a real decline in semen WHO parameters during a 10-year period, except for the percentage of morphologically abnormal spermatozoa, which dramatically increased over the years.

Testicular descent: INSL3, testosterone, genes and the intrauterine milieu

Complete testicular descent is a sign of, and a prerequisite for, normal testicular function in adult life. The process of testis descent is dependent on gubernacular growth and reorganization, which is regulated by the Leydig cell hormones insulin-like peptide 3 (INSL3) and testosterone. Investigation of the role of INSL3 and its receptor, relaxin-family peptide receptor 2 (RXFP2), has contributed substantially to our understanding of the hormonal control of testicular descent. Cryptorchidism is a common congenital malformation, which is seen in 2-9% of newborn boys, and confers an increased risk of infertility and testicular cancer in adulthood. Although some cases of isolated cryptorchidism in humans can be ascribed to known genetic defects, such as mutations in INSL3 or RXFP2, the cause of cryptorchidism remains unknown in most patients. Several animal and human studies are currently underway to test the hypothesis that in utero factors, including environmental and maternal lifestyle factors, may be involved in the etiology of cryptorchidism. Overall, the etiology of isolated cryptorchidism seems to be complex and multifactorial, involving both genetic and nongenetic components.

Cancer in first-degree relatives and risk of testicular cancer in Denmark

Familial aggregation of testicular cancer has been reported consistently, but it is less clear if there is any association between risk of testicular cancer and other cancers in the family. We conducted a population-based case-control study to examine the relationship between risk of testicular cancer and 22 different cancers in first-degree relatives. We included 3,297 cases of testicular cancer notified to the Danish Cancer Registry between 1991 and 2003. A total of 6,594 matched controls were selected from the Danish Civil Registration System, which also provided the identity of 40,104 first-degree relatives of case and controls. Familial cancer was identified by linkage to the Danish Cancer Registry, and we used conditional logistic regression to analyze whether cancer among first-degree relatives was associated with higher risk of testicular cancer. Rate ratio for testicular cancer was 4.63 (95% CI: 2.41-8.87) when a father, 8.30 (95% CI: 3.81-18.10) when a brother and 5.23 (95% CI: 1.35-20.26) when a son had testicular cancer compared to no familial testicular cancer. Results were similar when analyses were stratified by histologic subtypes of testicular cancer. Familial non-Hodgkin lymphoma and esophageal cancer were associated with testicular cancer; however, these may be chance findings. The familial aggregation of testicular and possibly other cancers may be explained by shared genes and/or shared environmental factors, but the mutual importance of each of these is difficult to determine.

Cancer risk diversity in non-western migrants to Europe: An overview of the literature

BACKGROUND

Cancer risk varies geographically and across ethnic groups that can be monitored in cancer control to respond to observed trends as well as ensure appropriate health care. The study of cancer risk in immigrant populations has great potential to contribute new insights into aetiology, diagnosis and treatment of cancer. Disparities in cancer risk patterns between immigrant and autochthonous populations have been reported many times, but up to now studies have been heterogeneous and may be discordant in their findings. The aim of this overview was to compile and compare studies on cancer occurrence in migrant populations from non-western countries residing in Western Europe in order to reflect current knowledge in this field and to appeal for further research and culturally sensitive prevention strategies.

METHODS

We included 37 studies published in the English language between 1990 and April 2010 focussing on cancer in adult migrants from non-western countries, living in the industrialised countries of the European Union. Migrants were defined based on their country of birth, ethnicity and name-based approaches. We conducted a between-country comparison of age-adjusted cancer incidence and mortality in immigrant populations with those in autochthonous populations.

FINDINGS

Across the board migrants from non-western countries showed a more favourable all-cancer morbidity and mortality compared with native populations of European host countries, but with considerable site-specific risk diversity: Migrants from non-western countries were more prone to cancers that are related to infections experienced in early life, such as liver, cervical and stomach cancer. In contrast, migrants of non-western origin were less likely to suffer from cancers related to a western lifestyle, e.g. colorectal, breast and prostate cancer.

DISCUSSION

Confirming the great cancer risk diversity in non-western migrants in and between different European countries, this overview reaffirms the importance of exposures experienced during life course (before, during and after migration) for carcinogenesis. Culturally sensitive cancer prevention programmes should focus on individual risk patterns and specific health care needs. Therefore, continuously changing environments and subsequently changing risks in both migrant and autochthonous populations need to be observed carefully in the future.

Gene-environment interaction and male reproductive function

As genetic factors can hardly explain the changes taking place during short time spans, environmental and lifestyle-related factors have been suggested as the causes of time-related deterioration of male reproductive function. However, considering the strong heterogeneity of male fecundity between and within populations, genetic variants might be important determinants of the individual susceptibility to the adverse effects of environment or lifestyle. Although the possible mechanisms of such interplay in relation to the reproductive system are largely unknown, some recent studies have indicated that specific genotypes may confer a larger risk of male reproductive disorders following certain exposures. This paper presents a critical review of animal and human evidence on how genes may modify environmental effects on male reproductive function. Some examples have been found that support this mechanism, but the number of studies is still limited. This type of interaction studies may improve our understanding of normal physiology and help us to identify the risk factors to male reproductive malfunction. We also shortly discuss other aspects of gene-environment interaction specifically associated with the issue of reproduction, namely environmental and lifestyle factors as the cause of sperm DNA damage. It remains to be investigated to what extent such genetic changes, by natural conception or through the use of assisted reproductive techniques, are transmitted to the next generation, thereby causing increased morbidity in the offspring.

Incidence of testicular cancer in the United States, 1999-2004

Testicular cancer is rare but primarily affects young men. To characterize the current incidence of testicular cancer in the United States, U.S. Cancer Statistics data from 1999 through 2004 were examined. Age-adjusted (2000 U.S. standard) incidence rates were calculated for seminoma and nonseminoma testicular germ cell tumors (TGCTs). Hispanic men had the largest increase in incidence rates for nonseminomas, followed by non-Hispanic White men (annual percentage change of 3.2% and 1.9%, respectively, p < .05). Nonseminomas peaked at a younger age for Hispanic, American Indian/Alaska Native (AIAN), and Asian/Pacific Islander (API) men. Whereas 9.6% of TGCTs were diagnosed at a distant stage in non-Hispanic White men, more Hispanic (16.1%), Black (13.8%), AIAN (16.8%), and API (14.9%) men with TGCTs were diagnosed with distant stage. Monitoring incidence rates for rare cancers by race/ethnicity has improved with national population-based cancer registry coverage. Disparities in diagnosis stage have implications for effective treatment of TGCTs.

Risk of testicular cancer according to birthplace and birth cohort in Denmark

Based on the intriguing finding of an east-west gradient of testicular cancer risk in the Nordic countries with a low risk in Finland, intermediate in Sweden, and high risk in Denmark, it was suggested that national practices rather than individual behavior may be important in the etiology of this cancer. We investigated the risk of testicular cancer in all men born in Denmark, 1931-1969 according to birthplace. Testicular cancer information was derived from the Danish Cancer Registry and population data from Statistics Denmark. There was a several fold geographical variation in testicular cancer risk within Denmark. Among men born in the early period, 1931-39, the highest risk was primarily observed in the western part of Denmark whereas no such gradient was observed in more recent cohorts. The incidence of testicular cancer increased in all counties from the earliest to the latest birth cohort, but the increase was highest in the eastern parts of Denmark. The heterogeneity in risk according to place of birth within Denmark suggests that individual behavior plays an important role for the risk of testicular cancer. Based on the Danish data, the factor that may have caused the east-west gradient in testicular cancer risk appears to have been more unevenly distributed in the early part of the past century compared to more recent times.

Testicular dysgenesis syndrome: foetal origin of adult reproductive problems

The evidence for the existence of testicular dysgenesis syndrome (TDS) is presented in this review. Several epidemiological studies have shown that conditions like cryptorchidism, impaired spermatogenesis, hypospadias and testicular cancer can be associated as risk factors for each other. Thus, the risk of testis cancer is significantly increased in men with cryptorchidism and/or infertility. Several recent studies point towards early dysgenesis of the foetal testis as the biological link between these disorders. Dysgenesis has been demonstrated in biopsies of the contralateral testis of men with testis cancer and in infertile men. The histological evidence includes immature seminiferous tubules with undifferentiated Sertoli cells, microliths and Sertoli-cell only tubules. Dysgenetic testes often have an irregular ultrasound pattern, where microliths may also be visible. Our current hypothesis is that maternal exposure to endocrine disrupting chemicals may contribute to the pathogenesis of TDS. Animal experiments have shown that all TDS symptoms, except testicular cancer, can be induced by foetal exposure to anti-androgenic chemicals. However, the cause of TDS in humans remains to be determined.

Social inequality and incidence of and survival from male genital cancer in a population-based study in Denmark, 1994-2003

We investigated the effects of socioeconomic, demographic and health-related indicators on the incidence of and survival from prostate and testicular cancer diagnosed 1994-2003 with follow-up through 2006 in Denmark using information from nationwide registers. The analyses were based on data on 8279 men with prostate cancer and 1770 with testicular cancer in a cohort of 3.22 million persons born between 1925 and 1973 and aged >or=30 years. We found that men with higher education and the highest disposable income had the highest incidence of prostate cancer. The 1-year and 5-year relative survival after prostate cancer were best amongst men of the highest socioeconomic position. We found no substantial social gradients in the incidence of or survival from testicular cancer.