Familial testicular cancer and urogenital developmental anomalies

Malignant Testicular Germ Cell Tumor in Father and Son: A Case Report

This is the eighteenth case of testicular tumor in a father and son reported in the literature. The father had a seminoma and the son an embryonal carcinoma. The trend favoring more malignant tumors occurring at younger ages in the sons is confirmed by this report.

Prospectively Identified Incident Testicular Cancer Risk in a Familial Testicular Cancer Cohort

BACKGROUND

Human testicular germ cell tumors (TGCT) have a strong genetic component and a high familial relative risk. However, linkage analyses have not identified a rare, highly penetrant familial TGCT (FTGCT) susceptibility locus. Currently, multiple low-penetrance genes are hypothesized to underlie the familial multiple-case phenotype. The observation that two is the most common number of affected individuals per family presents an impediment to FTGCT gene discovery. Clinically, the prospective TGCT risk in the multiple-case family context is unknown.

METHODS

We performed a prospective analysis of TGCT incidence in a cohort of multiple-affected-person families and sporadic-bilateral-case families; 1,260 men from 140 families (10,207 person-years of follow-up) met our inclusion criteria. Age-, gender-, and calendar time-specific standardized incidence ratios (SIR) for TGCT relative to the general population were calculated using SEER*Stat.

RESULTS

Eight incident TGCTs occurred during prospective FTGCT cohort follow-up (versus 0.67 expected; SIR = 11.9; 95% CI, 5.1-23.4; excess absolute risk = 7.2/10,000). We demonstrate that the incidence rate of TGCT is greater among bloodline male relatives from multiple-case testicular cancer families than that expected in the general population, a pattern characteristic of adult-onset Mendelian cancer susceptibility disorders. Two of these incident TGCTs occurred in relatives of sporadic-bilateral cases (0.15 expected; SIR = 13.4; 95% CI, 1.6-48.6).

CONCLUSIONS

Our data are the first to indicate that despite relatively low numbers of affected individuals per family, members of both multiple-affected-person FTGCT families and sporadic-bilateral TGCT families comprise high-risk groups for incident testicular cancer.

IMPACT

Men at high TGCT risk might benefit from tailored risk stratification and surveillance strategies.

Management of Low-Stage Testicular Seminoma

Management of testicular seminoma has benefited from numerous advances in imaging, radiotherapy, and chemotherapy over the last 50 years leading to nearly 100% disease-specific survival for low-stage seminoma. This article examines the evaluation and management of low-stage testicular seminoma, which includes clinical stage I and IIA disease. Excellent outcomes for stage I seminoma are achieved with active surveillance, adjuvant radiotherapy, and adjuvant single-agent carboplatin. Current areas of research focus on optimizing surveillance regimens and minimizing the morbidity and long-term complications of adjuvant treatment. Radiotherapy continues to be the primary treatment option for patients with clinical stage IIa disease.

Tumor loci and their interactions on mouse chromosome 19 that contribute to testicular germ cell tumors

BACKGROUND

Complex genetic factors underlie testicular germ cell tumor (TGCT) development. One experimental approach to dissect the genetics of TGCT predisposition is to use chromosome substitution strains, such as the 129.MOLF-Chr 19 (M19). M19 carries chromosome (Chr) 19 from the MOLF whereas all other chromosomes are from the 129 strain. 71% of M19 males develop TGCTs in contrast to 5% in 129 strain. To identify and map tumor loci from M19 we generated congenic strains harboring MOLF chromosome 19 segments on 129 strain background and monitored their TGCT incidence.

RESULTS

We found 3 congenic strains that each harbored tumor promoting loci that had high (14%-32%) whereas 2 other congenics had low (4%) TGCT incidences. To determine how multiple loci influence TGCT development, we created double and triple congenic strains. We found additive interactions were predominant when 2 loci were combined in double congenic strains. Surprisingly, we found an example where 2 loci, both which do not contribute significantly to TGCT, when combined in a double congenic strain resulted in greater than expected TGCT incidence (positive interaction). In an opposite example, when 2 loci with high TGCT incidences were combined, males of the double congenic showed lower than expected TGCT incidence (negative interaction). For the triple congenic strain, depending on the analysis, the overall TGCT incidence could be additive or could also be due to a positive interaction of one region with others. Additionally, we identified loci that promote bilateral tumors or testicular abnormalities.

CONCLUSIONS

The congenic strains each with their characteristic TGCT incidences, laterality of tumors and incidence of testicular abnormalities, are useful for identification of TGCT susceptibility modifier genes that map to Chr 19 and also for studies on the genetic and environmental causes of TGCT development. TGCTs are a consequence of aberrant germ cell and testis development. By defining predisposing loci and some of the locus interactions from M19, this study further advances our understanding of the complex genetics of TGCTs, which is the most common cancer in young human males.

Testicular cancer: a prototypic tumor of young adults

Testicular cancer is the most common solid tumor among males in the 20- to 39-year age range. Moreover, testicular cancer has unique biological associations, clinical features, and psychosocial impacts that establish this tumor as a prototypic malignancy of young adults. The biology of testicular germ cell tumors after puberty is distinctive. Epidemiologic patterns of testicular cancer suggest etiologic factors that may be congenital, racial, and geographic. The clinical management of a cancer common among young adults, but rare among adults in general, requires expertise so as not to jeopardize the high rates of survivorship associated with modern therapy. The concurrent but separate development of staging, prognostic systems, and treatment recommendations between the fields of pediatric and adult oncology highlights the need for increased integration and cooperation across these subspecialties. The high rate of survival, combined with the need for long-term monitoring for relapse or late effects, demonstrates the challenge of delivering longitudinal care in this mobile and active young adult population.

Chromosome X modulates incidence of testicular germ cell tumors in Ter mice

Germ cell tumor development in humans has been proposed to be part of testicular dysgenesis syndrome (TDS), which manifests as undescended testes, sterility, hypospadias, and, in extreme cases, as germ cell tumors. Males of the Ter mouse strain show interesting parallels to TDS because they either lack germ cells and are sterile or develop testicular germ cell tumors. We found that these defects in Ter mice are due to mutational inactivation of the Dead-end (Dnd1) gene. Here we report that chromosome X modulates germ cell tumor development in Ter mice. We tested whether the X or the Y chromosome influences tumor incidence. We used chromosome substitution strains to generate two new mouse strains: 129-Ter/Ter that carry either a C57BL/6J (B6)-derived chromosome (Chr) X or Y. We found that Ter/Ter males with B6-Chr X, but not B6-Chr Y, showed a significant shift in propensity from testicular tumor development to sterile testes phenotype. Thus, our studies provide unambiguous evidence that genetic factors from Chr X modulate the incidence of germ cell tumors in mice with inactivated Dnd1.

Testicular germ cell tumor susceptibility genes from the consomic 129.MOLF-Chr19 mouse strain

Chromosome substitution strains (CSS or consomic strains) are useful for mapping phenotypes to chromosomes. However, huge efforts are needed to identify the gene(s) responsible for the phenotype in the complex context of the chromosome. Here we report the identification of candidate disease genes from a CSS by using a combination of genetic and genomic approaches and by using knowledge about the germ cell tumor disease etiology. We used the CSS 129.MOLF-Chr19 chromosome substitution strain, in which males develop germ cell tumors of the testes at an extremely high rate. We were able to identify three protein-coding genes and one microRNA on chromosome 19 that have previously not been implicated to be testicular tumor susceptibility genes. Our findings suggest that changes in gene expression levels in the gonadal tissues of multiple genes from Chr 19 likely contribute to the high testicular germ cell tumor (TGCT) incidence of the 129.MOLF-Chr19 strain. Our data advance the use of CSS to identify disease susceptibility genes and demonstrate that the 129.MOLF-Chr19 strain serves as a useful model to elucidate the genetics and biology of germ cell transformation and tumor development.

Do all patients with bilateral testis cancer have a hereditary predisposition?

An international study has demonstrated that patients with bilateral testicular cancer are significantly more likely to have brothers with testis cancer than those with unilateral disease. This, together with other evidence, implies that patients with bilateral disease are likely to carry a predisposing genotype. But is it the great majority of them which is thus predisposed? We show that if as few as half of these patients have the predisposing genotype, its penetrance would have to be 80%, causing 38% of resulting cases to be bilateral. Evidence from the International Testis Cancer Linkage Consortium shows that the proportion of familial cases with bilateral disease is much lower. It is likely that at least the majority of cases of bilateral testis cancer arise as a result of a predisposing genotype.

Testicular germ-cell cancer

Testicular germ-cell tumours (TGCTs) represent the model of a curable malignancy; sensitive tumour markers, accurate prognostic classification, logical series of management trials, and high cure rates in both seminomas and non-seminomas have enabled a framework of effective cancer therapy. Understanding the molecular biology of TGCT could help improve treatment of other cancers. The typical presentation in young adults means that issues of long-term toxicity become especially important in judging appropriate management. A focus of recent developments has been to tailor aggressiveness of treatment to the severity of the prognosis. Recent changes affect the most common subtypes and include the reduction of chemotherapy for patients who have metastastic non-seminomas and a good prognosis, and alternatives to adjuvant radiotherapy in stage I seminomas. We summarise advances in the understanding and management of TGCT during the past decade.

A discussion of the biology of testicular cancer and current concepts in the management of stage I and bilateral disease

This case was the subject of a Grand Round Presentation at the Royal Marsden Hospital, Sutton, UK on 8 June 2004. A case of metachronous, bilateral testicular germ-cell tumours (TGCTs) arising in a patient with a family history of this disease was presented. The second primary was managed conservatively. The rationale and outcome of this approach was presented, along with a discussion of the management of early stage TGCTs and the genetics of familial and bilateral disease.

Subfertility and the risk of testicular germ cell tumors (United States)

OBJECTIVES

Previous studies have reported an association between subfertility and the risk of testicular germ cell tumors. We examined fertility, measured by number of children fathered and prior diagnosis of infertility, as a risk factor for testicular cancer, while accounting for the influence of occult cancer and cryptorchidism.

METHODS

Tumor registry data were used to identify 329 cases of testicular cancer in white men aged 20 to 69 years, diagnosed in western Washington State from 1977 to 1983; 672 cancer-free controls were identified by random-digit dialing. Telephone interviews ascertained reproductive histories and basic demographic information. Logistic regression was used to estimate the relative risk of testicular cancer associated with fertility.

RESULTS

Testicular cancer risk was decreased among men who had previously fathered a child (age-adjusted odds ratio (OR) 0.76, 95% confidence interval (CI): 0.54-1.06). Inverse associations were seen for seminomas and non-seminomas, and only slight attenuations in the ORs were observed when men with a history of cryptorchidism were excluded. Prior diagnosis of infertility was associated with an increased risk of testicular cancer (OR 2.40, 95% CI: 1.00-5.77).

CONCLUSIONS

These results are consistent with an increased risk of testicular cancer among men with reduced fertility that goes beyond the effects of cryptorchidism.

European consensus on diagnosis and treatment of germ cell cancer: a report of the European Germ Cell Cancer Consensus Group (EGCCCG)

Germ cell tumour is the most frequent malignant tumour type in young men with a 100% rise in the incidence every 20 years. Despite this, the high sensitivity of germ cell tumours to platinum-based chemotherapy, together with radiation and surgical measures, leads to the high cure rate of > or = 99% in early stages and 90%, 75-80% and 50% in advanced disease with 'good', 'intermediate' and 'poor' prognostic criteria (IGCCCG classification), respectively. The high cure rate in patients with limited metastatic disease allows the reduction of overall treatment load, and therefore less acute and long-term toxicity, e.g. organ sparing surgery for specific cases, reduced dose and treatment volume of irradiation or substitution of node dissection by surveillance or adjuvant chemotherapy according to the presence or absence of vascular invasion. Thus, different treatment options according to prognostic factors including histology, stage and patient factors and possibilities of the treating centre as well may be used to define the treatment strategy which is definitively chosen for an individual patient. However, this strategy of reduction of treatment load as well as the treatment itself require very high expertise of the treating physician with careful management and follow-up and thorough cooperation by the patient as well to maintain the high rate for cure. Treatment decisions must be based on the available evidence which has been the basis for this consensus guideline delivering a clear proposal for diagnostic and treatment measures in each stage of gonadal and extragonadal germ cell tumour and individual clinical situations. Since this guideline is based on the highest evidence level available today, a deviation from these proposals should be a rare and justified exception.

Testicular, Other Genital, and Breast Cancers in First-Degree Relatives of Testicular Cancer Patients and Controls

Previous studies showed an increased prevalence of testicular cancer among fathers and brothers of testicular cancer patients. We examined whether testicular, other genital, and breast cancers aggregate in parents and siblings of testicular cancer patients in a population-based case-control study, including males, ages 15 to 69 years at diagnosis, with primary malignant tumors of the testes or extragonadal germ cell tumors. Controls were ascertained through the mandatory registries of residents and frequency matched to the cases by age and region of residence. In a face-to-face interview, 269 cases and 797 controls provided health-related information on parents and siblings. We calculated odds ratios (OR) and corresponding 95% confidence intervals (95% CI) based on the generalized estimating equations technique, adjusting for the matching variables and relatives' age. Three (1.1%) fathers and eight (3.2%) brothers of cases were affected with testicular cancer compared with four (0.5%) fathers and two (0.2%) brothers of controls. The OR (95% CI) of familial testicular cancer was 6.6 (2.35-18.77). Only nonseminoma patients had fathers with testicular cancer, whereas the affected brothers were all related to seminoma patients. Overall, we found an increased risk for genital other than testicular cancers (OR 2.5, 95% CI 1.43-4.43). For breast cancer, we detected an increased risk in sisters (OR 9.5, 95% CI 2.01-45.16, adjusted for age of study participant and age of sister) but not in mothers. Our findings support the hypothesis that testicular and other genital cancers have a common familial component that may be due to genetic and shared exogenous factors such as estrogen exposure during fetal development.

Genetic predisposition to testicular germ-cell tumours

Testicular germ-cell tumours (TGCT) are the most common neoplasm in young men. Various studies have suggested the existence of an inherited predisposition to development of these tumours. Genome-wide screens subsequently provided evidence of a TGCT susceptibility gene on chromosome Xq27 (TGCT1) that might also predispose to cryptorchism. However, this putative gene has yet to be identified, and other TGCT susceptibility genes probably exist. Completion of the human gene map and advances in genetic research will facilitate further investigation of genetic predisposition to TGCT. Insight into inheritance of TGCT might lead to the identification of individuals at increased risk of developing the disorder, increase our understanding of the mutation pathways that lead to sporadic cases, and contribute to improvement in diagnosis and treatment. Clinicians should record the family history of cancer and urogenital differentiation defects in patients with TGCT.

Clinical epidemiology of testicular germ cell tumors

Clinical epidemiology is sometimes called the basic science of clinical medicine. In terms of the pathogenesis of testicular germ cell tumors (GCTs), clinical epidemiology analyzes suspected risk factors. The present review highlights the risk factors established so far and briefly summarizes those factors currently under investigation. In analogy to the methods of evidence based medicine, this review attributes levels of evidence to each of the putative risk factors. Level I represents highest quality of evidence while level V denotes the lowest level. So far, undescended testis (UDT), contralateral testicular GCT and familial testis cancer are established risk factors attaining high levels of evidence (levels I-III a). In a meta-analysis of 21 studies exploring the association of UDT with GCT risk, an over-all relative risk (RR) of 4.8 (95% confidence interval 4.0-5.7) was found. Contralateral testicular GCT involves a roughly 25-fold increased RR of GCT, while familial testis cancer constitutes a RR of 3-10. Infertility, testicular atrophy, and twin-ship represent risk factors with lesser levels of evidence (level III a). There is also some evidence for HIV infection being a predisposing factor for GCT (level IV a). Scrotal trauma is probably not associated with GCT risk. The estrogen excess theory implies high estrogen levels during the first trimester of pregnancy. As a consequence, primordial germ cells lose track of the normal developmental line and transform into premalignant cells that later become testicular intraepithelial neoplasia (TIN), the precursor of full-blown testicular GCT. Surrogate parameters for high gestational estrogen levels are investigated in case control studies. Such factors are maternal age >30 years, first-born, low birth weight, maternal breast cancer, high sex-ratio of siblings. So far, the sum of evidence is promising but still conflicting (especially for level III b). Another novel theory is the childhood nutrition hypothesis. This concept postulates a modulating or "catalyzing" effect by high dietary intake during childhood on the pathogenesis of testicular GCT. A surrogate parameter of early childhood nutrition is adult height. So far, 12 controlled studies have looked to the possible association of attained height and GCT risk of which six demonstrated a significant association. Thus, the sum of evidence corresponds to level III b. This concept is appealing because it would explain several hitherto unexplained epidemiological features of GCT.

Clinical manifestations of genetic instability overlap one another

Cancer syndromes are characteristic associations of specific malignancies with various congenital anomalies. In addition to such diseases, an increased prevalence in general of chromosomal instability, malformations, immunodeficiencies, altered growth and development, and reproductive loss has been observed in both childhood leukemias and solid tumors. The overlap among these congenital disorders suggests their common prenatal, possibly genetic origin and thus the existence of a nonspecific genetic instability leading to various clinical manifestations of disturbances in cell division. Seeking for related features in family members of a patient with malignancy may be of clinical value in detecting predisposition to cancer.

Localisation of susceptibility genes for familial testicular germ cell tumour

Approximately 1700 men in the United Kingdom develop testicular germ cell tumours (TGCT) per year. Among the known risk factors a family history of disease remains one of the strongest (1, 2). Two-percent of TGCT cases report another affected family member. Epidemiological studies have shown that there is an eight to ten fold increase in relative risk of TGCT to brothers of patients and a fourfold increased risk to fathers and sons (2-5). This relative risk is considerably higher than for most other common cancers, which rarely exceeds four and strongly suggests that genes may play an important role in TGCT. Linkage analysis of the set of families compatible with X-linkage (i.e. no male to male transmission) provided the first statistically significant evidence for a TGCT predisposition locus (6). The gene called TGCT1 is located at Xq27 and seems to be associated with a risk of bilateral disease and undescended testis. However TGCT1 does not account for all TGCT pedigrees and additional susceptibility genes must exist. Our group has now genotyped 179 TGCT pedigrees and identified additional genomic regions that might also harbour TGCT susceptibility genes. This paper reviews the current data for the region at Xq27 and presents evidence for several other possible candidate regions.

Testicular carcinoma and HLA Class II genes

BACKGROUND

The association with histocompatibility antigens (HLA), in particular Class II genes (DQB1, DRB1), has recently been suggested to be one of the genetic factors involved in testicular germ cell tumor (TGCT) development. The current study, which uses genotyping of microsatellite markers, was designed to replicate previous associations.

METHODS

In 151 patients, along with controls comprising parents or spouses, the HLA region (particularly Class II) on chromosome 6p21 was genotyped for a set of 15 closely linked microsatellite markers.

RESULTS

In both patients and controls, strong linkage disequilibrium was observed in the genotyped region, indicating that similar haplotypes are likely to be identical by descent. However, association analysis and the transmission disequilibrium test did not show significant results. Haplotype sharing statistics, a haplotype method that derives extra information from phase and single marker tests, did not show differences in haplotype sharing between patients and controls.

CONCLUSION

The current genotyping study did not confirm the previously reported association between HLA Class II genes and TGCT. As the HLA alleles for which associations were reported are also prevalent in the Dutch populations, these associations are likely to be nonexistent or much weaker than previously reported.

Familial testicular cancer and second primary cancers in testicular cancer patients by histological type

The Swedish Family-Cancer Database was used to assess familial cancer risks in first-degree relatives and the risks of second primary cancers in testicular cancer patients by the histological type of their testicular cancers. Standardised incidence ratios (SIRs) were employed to estimate cancer risks. Among 4650 patients, 1.3% were familial testicular cancer. Seminomas showed a 10 years later median age of onset than teratomas (30 versus 40 years). The familial risks of testicular cancer were 3.8 for fathers, 8.3 for brothers and 3.9 for sons; they were similar for the two histologies. The fraternal risks were elevated 2- to 2.8-fold for pure histologies compared with the mixed histologies. Significantly increased risks for subsequent cancers were observed in the stomach, pancreas, testis, kidney, bladder, thyroid and connective and lymphatic tissues in the patients. Our data support the contention that genetic predisposition is one of the major contributors to familial and multiple testicular cancers.

Familial/bilateral and sporadic testicular germ cell tumors show frequent genetic changes at loci with suggestive linkage evidence

Testicular germ cell tumor (TGCT) is the most common tumor type among adolescent and young adult males. Familial clustering and bilateral disease are suggestive of a genetic predisposition among a subgroup of these patients, but susceptibility genes for testicular cancer have not yet been identified. However, suggestive linkage between disease and genetic markers has been reported at loci on chromosome arms 3q, 5q, 12q, 18q, and Xq. We have analyzed primary familial/bilateral (n=20) and sporadic (n=27) TGCTs, including 28 seminomas and 19 nonseminomas, for allelic imbalance (AI) within the autosomal regions. DNA from all tumors were analyzed by fluorescent polymerase chain reaction of 22 polymorphic loci at 3q27-ter, 5q13-35.1, 12q21-ter, and 18q12--ter. All tumor genotypes were evaluated against their corresponding constitutional genotypes. The percentages of TGCTs with genetic changes at 3q, 5q, 12q, and 18q, were 79%, 36%, 53% and 43%, respectively. The frequencies at 3q and 12q in nonseminomas were significantly higher than in seminomas (P=.003 and P=.004). In order to evaluate changes at hemizygous Xq loci, five loci were analyzed by co-amplification with an autosomal reference marker known to reveal retained heterozygosity in the tumor DNA. Gain of Xq sequences was seen in more than 50% of the tumors. The degree of amplification varied among the loci in each of five tumors, and based on these breakpoints, a common region of overlapping gains was found at Xq28. No significant differences were found between the frequencies of genetic changes in familial/bilateral versus sporadic tumors, an observation speaking in disfavor of the existence of a single susceptibility gene for TGCT in any of the analyzed regions. Our data suggest that gain of genetic material at distal Xq and losses at 5q and 18q contribute to establishment of seminomas, whereas imbalances at 3q as well as gain at distal part of 12q are associated with further progression into nonseminomas.

Cancer incidence in relatives of patients with testicular cancer in the eastern part of The Netherlands

OBJECTIVES

To investigate the incidence of malignant tumors in first-degree relatives of patients with testicular cancer.

METHODS

Information about the occurrence of cancer in relatives of patients treated for testicular germ cell cancer (TC) at the Department of Urology of the University Medical Centre Nijmegen from 1986 to 1997 was collected using postal questionnaires from 379 (72%) of 524 patients. The expected numbers of cancers in relatives were computed from age- and sex-specific incidence data in the Netherlands Cancer Registry. The observed/expected (O/E) ratios with 95% confidence intervals (CIs) were calculated using Byar's approximation of the exact Poisson test.

RESULTS

The O/E ratio for developing cancer in the families of patients with TC was 1.2 (95% CI 1.0 to 1.3). Among first-degree relatives of patients with TC, more TC was observed than expected (O/E 3.3; 95% CI 1.4 to 6.9). The risk for brothers of patients with TC increased 5.9-fold (95% CI 2.2 to 12.8). Both the risk of developing lung cancer (O/E 1.5) and malignancy of the female genital tract in sisters (O/E 2.8) was slightly increased. In contrast, the risk of urinary tract malignancies (O/E 0.3) and other and unknown primary tumors (O/E 0.2) had a lower incidence among relatives. However, both the increased and decreased risk of nontesticular cancer for first-degree relatives may have been caused by misclassification.

CONCLUSIONS

TC clusters in families were more pronounced among brothers than among fathers and sons. This study supports previous reports that families of patients with TC do not seem to be prone to nontesticular cancer. Additional investigations in families with TC are recommended to map candidate genes for TC.

Localization to Xq27 of a susceptibility gene for testicular germ-cell tumours

Testicular germ-cell tumours (TGCT) affect 1 in 500 men and are the most common cancer in males aged 15-40 in Western European populations. The incidence of TGCT has risen dramatically over the last century. Known risk factors for TGCT include a history of undescended testis (UDT), testicular dysgenesis, infertility, previously diagnosed TGCT (ref. 7) and a family history of the disease. Brothers of men with TGCT have an 8-10-fold risk of developing TGCT (refs 8,9), whereas the relative risk to fathers and sons is fourfold (ref. 9). This familial relative risk is much higher than that for most other types of cancer. We have collected samples from 134 families with two or more cases of TGCT, 87 of which are affected sibpairs. A genome-wide linkage search yielded a heterogeneity lod (hlod) score of 2.01 on chromosome Xq27 using all families compatible with X inheritance. We obtained a hlod score of 4.7 from families with at least one bilateral case, corresponding to a genome-wide significance level of P=0.034. The proportion of families with UDT linked to this locus was 73% compared with 26% of families without UDT (P=0.03). Our results provide evidence for a TGCT susceptibility gene on chromosome Xq27 that may also predispose to UDT.

Geographic clustering of testicular cancer incidence in the northern part of The Netherlands

Geographic variations in testicular cancer incidence may be caused by differences in environmental factors, genetic factors, or both. In the present study, geographic patterns of age-adjusted testicular cancer incidence rates (IRs) in 12 provinces in The Netherlands in the period 1989-1995 were analysed. In addition, the age-adjusted IR of testicular cancer by degree of urbanization was evaluated. Cancer incidence data were obtained from the Netherlands Cancer Registry. The overall annual age-adjusted IR of testicular cancer in The Netherlands in the period 1989-1995 was 4.4 per 100000 men. The province Groningen in the north of the country showed the highest annual IR with 5.8 per 100000 men, which was higher (P < 0.05) than the overall IR in The Netherlands (incidence rate ratio (IRR) 1.3, 95% confidence interval (CI) 1.1-1.6). The highest IR in Groningen was seen for both seminomas and non-seminomas. In addition, Groningen showed the highest age-specific IRs in all relevant younger age groups (15-29, 30-44 and 45-59 years), illustrating the consistency of data. The province Friesland, also situated in the northern part of the country, showed the second highest IR of testicular cancer with 5.3 cases per 100000 men per year (IRR 1.2, 95% CI 1.0-1.5, not significant). This mainly resulted from the high IR of seminoma in Friesland. Analysis of age-adjusted IRs of testicular cancer by degree of urbanization in The Netherlands showed no urban-rural differences at analysis of all histological types combined, or at separate analyses of seminomas and non-seminomas. Geographic clustering of testicular cancer seems to be present in the rural north of The Netherlands with some stable founder populations, which are likely to share a relatively high frequency of genes from common ancestors including genes possibly related to testicular cancer. Although this finding does not exclude the involvement of shared environmental factors in the aetiology of testicular cancer, it may also lend support to a genetic susceptibility to testicular cancer development. Testicular cancer cases in stable founder populations seem particularly suitable for searching for testicular cancer susceptibility genes because such genes are likely to be more frequent among affected men in such populations.

Familial testicular cancer in a single-centre population

Familial occurrence of testicular cancer suggests a genetic predisposition to the disease. A genetic susceptibility may also be reflected by the occurrence of bilateral testicular neoplasms and the high rates of urogenital developmental anomalies in families prone to testicular cancer. In this study, the proportion of familial testicular cancer cases was analyzed retrospectively in a single-centre population of 693 testicular cancer patients treated between 1977 and 1997 and the relative risk (RR) for first-degree relatives of patients was estimated. In addition, the existence of bilateral testicular neoplasms and urogenital developmental anomalies in familial testicular cancer patients was evaluated. 24 of the 693 patients (3.5%) had a first-degree relative with testicular cancer. These 24 cases belonged to 17 families; in 7 of these 17 families both affected first-degree family members were part of the study population of 693 patients. Consequently, the 693 studied patients belonged to a total of 686 families. Thus, the actual proportion of familial testicular cancer was 2.5% (17 of 686 families). The familial cases consisted of 11 brother pairs, including 2 pairs of identical twins and 1 pair which also had two affected cousins, and 6 father-son pairs (in total 36 cases, 12 treated elsewhere). Estimates of the RR to first-degree relatives showed a 9- to 13-fold increased RR to brothers (P < 0.001) and a 2-fold increased RR to fathers (P = non-significant (n.s)) of testicular cancer patients. Among the 36 patients with familial testicular cancer, 2 (5.6%) had bilateral testicular cancer, 4 (11.1%) had undescended testis, 3 (8.3%) had inguinal hernia, and 1 (2.8%) showed renal hypoplasia. The present data on familial occurrence of testicular cancer may lend support to a role of genetic factors in the aetiology of testicular cancer.

Young men's knowledge of testicular cancer and testicular self-examination: a lost opportunity?

Testicular cancer remains the most commonly occurring cancer in young men (aged 20-45 years) and recent trends suggest an increase throughout the western world. Whilst testicular cancer is highly treatable late diagnosis resulting in poorer treatment outcomes remains a problem. Testicular self-examination (TSE) a procedure whereby young men can routinely systematically examine their testicles has been advocated as a particularly effective health education intervention. This study aimed to establish the knowledge of testicular cancer and prevalence of TSE practice amongst young men. A descriptive survey approach using a 16-item self-report questionnaire was administered to a convenience sample of 203 male undergraduate and postgraduate students at the University of Huddersfield. Results indicated that the majority of the respondents were either uninformed or misinformed about the risks and symptoms of testicular cancer although 78% indicated an interest in accessing information. Only 32% had prior knowledge of TSE, 22% practiced TSE, and worryingly only a single respondent was able to recognize the correct procedure and indicated he regularly practiced TSE. Sixty-eight per cent indicated that TSE should be a part of general health assessments for men. Although some critics of TSE argue the cost of teaching TSE outweighs the benefits in terms of early diagnosis this study suggests that young men may be willing to participate in an aspect of personal health surveillance. If this is the case then low cost strategies to increase impact on the target audience should be considered.

Risk factors for testicular cancer: a case-control study in twins

Early life and anthropometric risk factors for testicular cancer were examined in a case-control study in England and Wales in which affected male twins were compared with their unaffected male co-twins. Questionnaire data was obtained for 60 twin pairs. Significantly raised risk of testicular cancer occurred in twins who had longer arms and legs than their co-twin. There was a significant excess of testicular cancer reported in non-twin brothers, as well as in twin brothers, of cases. Risk was also significantly raised in relation to cryptorchidism. The results on limb length suggest that factors, perhaps nutritional, affecting growth before puberty, may be causes of testicular cancer. The results on risk in brothers add to evidence of a large genetic component in aetiology of the tumour. The risk associated with cryptorchidism in the twins accords with the hypothesis that cryptorchidism is causally associated with testicular cancer because it is a cause of the malignancy, rather than because the same maternal factors experienced in utero cause both conditions.

Testicular germ cell tumors: molecular understanding and clinical implications

It was recognized in the 1960s that testicular germ cell tumors were curable with chemotherapeutic drugs. Since that time, newer drugs including cisplatin have increased the cure rate of these tumors to over 80%, even in patients with metastatic disease. Germ cell tumors also exhibit a unique biology and genetics that distinguish them from other solid tumors and might contribute to their routine curability.

Risk and prognostic factors in testicular tumours: 3 emblematic observations

The authors report 3 clinical cases of testicular tumour considered emblematic regarding genesis and development, and highlight the close connection between testicular tumours and some of the known risk and prognostic factors.

Germ cell tumours in a brother and sister

In familial germ cell tumour cases, a normal chromosomal karyotype pattern is rare. We report the findings of germ cell tumours in two siblings with a normal chromosomal karyotype. One of these patients had dysgerminoma in the right ovary and was treated successfully for this. At present, she is 23 years old and has two daughters. The other patient is a 15-year-old boy, who is the brother of the first patient and has mediastinal embryonal carcinoma. Although ultrasonography of the testes showed irregularity in the shape and non-homogeneity of the parenchyma, histopathological examination was found to be normal at the time of diagnosis. At present, he is doing well and his chemotherapy is continuing. Both of them have a normal chromosomal karyotype, 46, XX and 46, XY, respectively. We suggest that children who have a sibling with germ cell tumour should be carefully assessed for development of another germ cell tumour.

High-resolution HLA-DRB1 and DQB1 genotyping in Japanese patients with testicular germ cell carcinoma

We report for the first time the frequency distributions of HLA-DRB1 and -DQB1 genes in 55 patients with testicular germ cell carcinoma (TGC) using the modified PCR-RFLP method and compare the results with those for 1216 healthy Japanese control subjects. The modified PCR-RFLP method produced accurate, reproducible cleavage patterns that are easily discriminated. HLA-DRB1*0410 was the susceptibility allele (RR = 3.26, P = 0.006) and DQB1*0602 appears to be a candidate protective allele (RR = 0.26, P = 0.02) for TGC in the Japanese. None of the HLA-DRB1 and -DQB1 alleles showed a specific tendency for histological type or clinical stage of the tumours. Previous studies based on serotyping methods failed to show these allelic associations. High-resolution genotyping is essential because the peptide-binding domain of MHC class II molecules is determined more precisely by their genotypes than by their serotypes. In addition, inherent technical difficulties and typing errors of up to 25% make serotyping inefficient. Our results suggest that high-resolution genotyping is a useful genetic marker to determine risk for TGC.

A segregation analysis of testicular cancer based on Norwegian and Swedish families

Clustering of testicular cancer cases in families is well known, although the aetiology is not. We present the results of a segregation analysis performed with the algorithm Pointer on familial data on 978 Scandinavian patients with testicular cancer. The segregation analysis favoured the involvement of major gene effects over models incorporating solely polygenic effects in testicular cancer aetiology. Overall, a recessive model best fits the family observations with an estimated gene frequency of 3.8% and a lifetime risk for homozygous men of developing the disease of 43%. This implies that 7.6% of men in the general population will be carriers of the mutant allele and that 0.1% would be homozygote and are, therefore, at high risk of developing the cancer. The testicular cancer incidence has changed greatly during the last generation. Also, the lethality of the disease has changed because of the introduction of new therapy. As failure to take account of such time trends might lead to inappropriate evidence for a recessive model, the analyses were repeated under different assumptions. The analyses favoured a recessive model of inheritance under all assumptions tested. However, the assumptions underlying the analyses are complex and, as this is the first segregation analysis of testicular cancer, the results must be interpreted cautiously.

Cancer risk in fathers and brothers of testicular cancer patients in Denmark. A population-based study

There are several reports of familial testicular cancer in the literature but few systematic attempts have been made to estimate the risk of testicular cancer in first-degree relatives of patients with this neoplasm, and the risk remains to be fully assessed in population-based studies. By means of data from the Danish Cancer Registry, we identified all testicular cancer patients (index cases) born and diagnosed during 1950-1993 in Denmark. Their fathers were identified from national registries, as were the brothers of a subcohort of these patients. Familial cancer occurrence was determined through linkage with the cancer registry and compared with the cancer incidence in the general male population in Denmark. The ratio of observed to expected cancers generated the measure used for the relative risk. Fathers of 2,113 index cases with testicular cancer experienced an almost 2-fold risk of developing testicular cancer themselves (RR = 1.96; 95% CI: 1.01-3.43). Overall, the fathers had a decreased relative cancer risk (RR = 0.84; 95% CI: 0.74-0.95) with a significantly decreased risk of cancers of the lung and digestive organs. Brothers of a subcohort of 702 index cases showed a markedly increased risk of testicular cancer (RR = 12.3; 95% CI: 3.3-3 1.5). In conclusion, we documented a significantly increased familial risk of testicular cancer which was relatively more pronounced between brothers than between fathers and sons. These findings support the possible involvement of a genetic component in the aetiology of testicular cancer, but also leave room for a hypothesized influence of in-utero exposures, such as specific maternal hormone levels, that might be shared by brothers.

Familial testicular cancer in Norway and southern Sweden

Information about occurrence of testicular cancer (TC) in relatives of TC patients has been collected using questionnaires from 797 out of 922 consecutive Norwegian and 178 out of 237 Swedish patients with TC seen at the Norwegian Radium Hospital and the University Hospital Lund in Sweden during 1981-91. Fifty-one Norwegian and five Swedish patients had a relative with confirmed TC. Thus, 51/922 (5.5%) of the Norwegian and 5/237 (2.1%) of the Swedish patients treated during the time interval investigated were considered to have familial TC. Thirty-two of the patients had an affected first-degree relative. Expected numbers of cancers in the relatives were computed from data in the Norwegian and Swedish Cancer Registries. Standardised incidence ratios (SIRs) were taken as observed numbers of TC/expected numbers of TC in the relatives. The SIR for brothers was 10.2 (95% confidence interval 6.22-15.77). SIR for fathers was 4.3 (1.6-9.3) and for sons 5.7 (0.7-23.2). The point estimate for the risk to brothers in the Norwegian part of the sample to develop TC by the age of 60 was 4.1% (95% CI 1.7-6.6%). This study indicates that genetic factors may be of greater importance in TC than previously assumed. Patients with familial testicular cancer had bilateral tumours more often than sporadic cases (9.8% bilaterality in familial vs 2.8% in sporadic cases, P=0.02). For patients with seminoma age of onset was lower in familial than in sporadic cases (32.9 vs 37.6 years, P=0.06). In father-son pairs, there was a statistically significant earlier age of diagnosis in the generation of sons (28.8 years vs 44.9 years, P=0.04). The prevalence of undescended testis (UDT) did not seem to be higher in familial than in sporadic TC (8.2% in familial TC and 13.3% in sporadic cases). This may indicate that different factors are of importance for the development of familial TC and UDT.

Testicular cancer, cryptorchidism, inguinal hernia, testicular atrophy, and genital malformations: case-control studies in Denmark

To explore risk factors for testicular cancer and cryptorchidism, two parallel case-control studies were conducted in Denmark. The testicular cancer study was population-based and included 514 cases and 720 controls. The cryptorchidism study included 387 cases and 416 controls and was based on two hospital series of men treated for cryptorchidism and a control group sampled among residents in the Copenhagen area. The 2,037 men were interviewed by telephone. The relative risk (RR) of testicular cancer in men with treated or persisting cryptorchidism was 3.6 (95 percent confidence interval = 1.8-6.9), but no increase in risk was seen in the six to seven percent of the men who reported a history of undescended testes that descended spontaneously. The RR in men who were treated for cryptorchidism increased with age at treatment. This effect may be due wholly or in part to increased treatment of boys with testes that would have descended spontaneously if they had not been treated. Cryptorchidism and inguinal hernia may be confused and reported interchangeably. In the absence of cryptorchidism or testicular atrophy, clinical inguinal hernia was not associated with testicular cancer. Testicular atrophy was associated with both testicular cancer and cryptorchidism. Associations with other congenital malformations were few and based on small numbers.

Testicular cancer in father and son

The occurrence of testicular tumors in closely related family members is rare. We report a case of testicular cancers in a father and son. The father had pure seminoma, and his son developed a mixed nonseminomatous germ cell tumor. The peripheral blood lymphocytes in both patients were tested for 52 HLA specificities, and the patients were found to have six in common. The son was homozygous for HLA A24. The association between certain HLA antigens, other genetic factors, and testicular cancer requires further study to improve the care and counseling of patients and their families.

Inheritance and testicular cancer

Statistical analysis of published data on the age of onset of germ cell tumours of the testis and of the prevalence of bilateral disease in familial and general cases suggest the following: 1. Patients with bilateral disease carry the same genetic predisposition as familial cases. 2. Males with the hereditary predisposition develop none, unilateral or bilateral tumours in the proportions 55%, 38% and 7% respectively. 3. One-third of all testis cancer patients are genetically predisposed to the disease. 4. The 2.2% risk to brothers of cases as reported elsewhere can be accounted for by the homozygous (recessive) inheritance of a single predisposing gene.

Germinoma in siblings: case reports

We present the first reported cases of germinoma occurring in siblings of different genders. One tumor occurred in the left basal ganglia of a 7-year-old boy and the other in the suprasellar region of his 9-year-old sister. Both tumors were diagnosed as germinoma of two-cell pattern based on light and electron microscopic studies. Possible genetic factors responsible for this phenomenon are discussed.

Familial occurrence of testicular cancer

The etiology of testicular cancer is unknown. Familial testicular cancer is a rare entity that adds further information to research regarding the genetic influence on germ cell tumors. We report on 5 brothers, including 2 identical triplets and 1 fraternal brother, with testicular cancer and discuss the epidemiological factors. It appears that environmental and genetic factors must be considered.