Inheritance and testicular cancer. Arguments based on a report of 3 cases and a review of the literature

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.

Origins and molecular biology of testicular germ cell tumors

Testicular germ cell tumors can be divided into three groups (infantile/prepubertal, adolescent/young adult and spermatocytic seminoma), each with its own constellation of clinical histology, molecular and clinical features. They originate from germ cells at different stages of development. The most common testicular cancers arise in postpubertal men and are characterized genetically by having one or more copies of an isochromosome of the short arm of chromosome 12 [i(12p)] or other forms of 12p amplification and by aneuploidy. The consistent gain of genetic material from chromosome 12 seen in these tumors suggests that it has a crucial role in their development. Intratubular germ cell neoplasia, unclassified type (IGCNU) is the precursor to these invasive tumors. Several factors have been associated with their pathogenesis, including cryptorchidism, elevated estrogens in utero and gonadal dysgenesis. Tumors arising in prepubertal gonads are either teratomas or yolk sac tumors, tend to be diploid and are not associated with i(12p) or with IGCNU. Spermatocytic seminoma (SS) arises in older patients. These benign tumors may be either diploid or aneuploid and have losses of chromosome 9 rather than i(12p). Intratubular SS is commonly encountered but IGCNU is not. The pathogenesis of prepubertal GCT and SS is poorly understood.

Germ cell tumours of the testis

Cancer of the testis is a relatively rare disease, accounting for about 1% of all cancers in men. Cryptorchidism is the only confirmed risk factor for testicular germ cell tumour. The majority of GCT are clinically detectable at initial presentation. Any nodular, hard, or fixed area discovered in the testis, must be considered neoplastic until proved otherwise. The appropriate surgical procedure to make the diagnosis is a radical orchidectomy through an inguinal incision. Many GCT produce tumoural markers (AFP, HCG, LDH), who are useful in the diagnosis and staging of disease; to monitor the therapeutic response and to detect tumour recurrence. In 1997 a prognostic factor-based classification for the metastatic germ cell tumours was developed by the IGCCCG: good, intermediate and poor prognosis, with 5-year survival of 91, 79 and 48%, respectively. GCT of the testis is a highly table, often curable, cancer. Germ cell testicular cancers are divided into seminoma and non-seminoma types for treatment planning because seminomatous testicular cancers are more sensitive to radiotherapy. Seminoma (all stages combined) has a cure rate of greater than 90%. For patients with low-stage disease, the cure approaches 100%. For patients with non-seminoma tumours, the cure rate is >95% in stages I and II; it is approximately 70% with standard chemotherapy and resection of residual disease, if necessary, in stages III and IV. Minimum guidelines for clinical, biochemical, and radiological follow-up have been reported by ESMO in 2001.

Testicular cancers occurring in brothers with cryptorchism

We report a case of familial testicular cancer associated with undescended testes in two brothers. The older brother (49 years) presented with a testicular tumor located in the right inguinal canal. The pathologic diagnosis was pure seminoma. Computerized tomography revealed iliac and retroperitoneal lymph node metastases. Four years later, the younger brother (44 years) developed bilateral testicular tumors, one located in the inguinal canal, the other located in the pelvic cavity. The pathologic diagnosis of both tumors was pure seminoma. Radiological examination revealed retroperitoneal lymph node metastases. Both patients received cisplatin-based combination chemotherapy as the initial treatment. The older brother suffered from repeated recurrences with lymph node metastases in the iliac and inguinal regions, but he was successfully treated with high-dose chemotherapy. The younger brother achieved long-term remission after retroperitoneal lymph node dissection following initial chemotherapy. We briefly review the reported cases of familial testicular cancer and discuss the association of the maldescent of the testes and familial testicular cancer cases.

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.

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.

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.

Familial testicular carcinoma: in search of genetic triggers

Two cases of testicular tumours in non-twin brothers of a cancer-prone family are described. Cytogenetic studies of these two patients and human leucocyte antigen (HLA) typing of the family failed to identify any genetic defects. The authors propose using linkage analysis for further genetic studies but would require additional families for this to be performed.

Precocious puberty in a child with unilateral Leydig cell tumor of the testis following orchiopexy

A case of right testicular Leydig cell tumor in a 10 1/2-year-old child with precocious puberty is reported. Significant history included right orchiopexy for cryptorchidism when the boy was 7 years old. The literature is reviewed and this disease entity is discussed.

Testicular cancer and cryptorchidism

The records of 273 patients with germ cell tumours of the testis referred between 1970 and July 1991 were reviewed. There were 25 (9%) black, 40 (14%) mixed race and 214 (77%) white patients. Histology showed seminoma in 53% and non-seminomatous and germ cell tumours in 47% of patients. Maldescent of the testis (MDT) was found in 30 patients--an incidence of 11% overall. MDT was present in 8 of 25 (32%) black, 7 of 40 (18%) mixed race and 15 of 214 (7%) white patients with testicular cancer. The incidence of MDT was statistically significantly higher in both black and mixed race patients compared with white patients. None of the black patients had undergone orchiopexy but 71% of mixed race and 87% of white patients had done so. This resulted in a different pattern of presentation in black compared with mixed race and white patients with MDT and testicular cancer. The mean age was 40 years for black, 32 years for mixed race and 33 years for white patients. Black patients presented with abdominal or inguinal tumours rather than scrotal tumours and they had an increased tendency to present with seminomas.

High resolution chromosome banding in search of germ line mutations applied on testicular cancer patients

Patients with bilateral and/or familial testicular cancer are assumed to demonstrate germ line mutations if such mutations are instrumental in testicular cancer patients. Constitutional rearrangements have to our knowledge not been reported, while an increased level of constitutional chromosome instability has been claimed. Lymphocytes from 12 Norwegian patients with bilateral or familial testicular cancer have been studied by high resolution Giemsa banding. A possible germ line mutation would be expected to be seen in every cell. It is therefore sufficient to examine one pair of the individual chromosomes obtained, if necessary, from several cells. Based on our previous findings of loss of heterozygosity in the chromosome regions 3p and 11p in testicular tumors, these chromosome arms were paid special attention. However, no mutations were observed in these regions nor in any other chromosome. Applying a 95% confidence interval, we conclude that less than 23% of familial and/or bilateral testicular cancer patients are caused by germ line mutations large enough to be detected with high resolution banding of at least 450 G-bands per haploid genome. The presented analyses were used to standardize the resolution determination in our laboratory.

Familial testicular cancer: a report of the UK family register, estimation of risk and an HLA class 1 sib-pair analysis

Forty-two families with two or more cases of testicular cancer have been reported to the UK Register for Familial Testicular Cancer, comprising two pairs of identical twins, 27 sets of other brothers (25 pairs, two triples), nine father-son pairs, two pairs of first cousins and two uncle-nephew pairs. In total 91 testicular tumours are described in 86 individuals (42 (46%) pure seminoma, 49 (54%) other germ cell tumours). The median age at diagnosis in these patients was significantly younger than that in a comparable series of non-familial patients (29 c.f. 32.5 years, P less than 0.01). In a case-control comparison of 794 testicular cancer patients, eight patients (1.0%) had a brother and four patients (0.5%) had a father with a previous diagnosis of testicular cancer at the time of their own diagnosis (and these families are all included in this report). Two out of 794 controls (0.3%) had a first degree relative with testicular cancer. The cumulative risk to a brother of a patient for developing testicular cancer by the age of 50 years was estimated to be 2.2% (95% C.I. 0.6-3.8%) which results in a relative risk of 9.8 (95% C.I. 2.8-16.7) in comparison with the general population. HLA Class I typing of 21 affected sib-pairs demonstrated four (19%) sharing two haplotypes, 13 pairs (62%) sharing one and four pairs (19%) sharing none. This did not differ significantly from the expected proportions of 25%/50%/25%. It is unlikely, therefore, that there is a major gene associated with testicular cancer predisposition within or closely linked to the major histocompatibility gene complex on chromosome 6.

Testicular adenoma and seminal vesicle engorgement in polyomavirus large-T antigen transgenic mice

Six lines of transgenic mice harboring the cDNA for polyomavirus large-T antigen (PVLT) linked to the mouse metallothionein-1 promoter were isolated. The transgene was expressed in testes in all lines isolated and in testes and seminal vesicles in two lines. Three lines developed enlarged testes and seminal vesicles. Development of the phenotype was divided into three stages separable by age and pathology. In stage 1, birth to 6 mo, PVLT was expressed in testes but no pathology was noted; in stage 2, 6-10 mo, PVLT was expressed solely in testes and not in seminal vesicles, yet the seminal vesicles were enlarged; and in stage 3, 10 mo and older, both testes and seminal vesicles expressed PVLT and both were enlarged. Testes were up to sevenfold heavier and increased up to fourfold to fivefold in each dimension. Seminal vesicles were enlarged up to 20-fold as the result of an accumulation of seminal vesicle fluid. In addition to the four major proteins of seminal vesicle fluid, extra proteins, initially found in stage 2, were increased in stage 3 seminal vesicle fluid. The Leydig cell was the dominant cell type in affected testes; there were few or no normal Sertoli cells or seminiferous tubules remaining by stage 3. The Leydig cells were physiologically active, as indicated by a 8.5-fold higher testosterone level in sera from stage 3 affected mice compared with sera from age-matched normal males. PVLT was present in the nuclei of the Leydig cells and was able to confer an immortal phenotype in vitro. Formation of the Leydig cell adenoma was dependent on PVLT expression, but since PVLT expression occurred much earlier than did pathology, additional secondary factors must determine the delay in phenotype development.

Risk factors for bilateral testicular germ cell tumors. Does heredity play a role?

Twenty-three bilateral testicular germ cell tumors (four synchronous and 19 sequential tumors) were investigated for potential risk factors. The incidence of maldescensus testis was not found to be higher than in patients with unilateral disease. The histologic findings of the first tumor did not have any effect on the incidence of the second tumor. In 21 patients (four synchronous and 17 sequential tumors), histocompatibility antigens (HLA) were determined; HLA-B14 was increased significantly in the sequential tumor group. Tendencies toward an increase of HLA-DR5 and HLA-DR7 also were found. The HLA-DR1, HLA-DR3, and HLA-DR4 showed a tendency toward a decreased frequency. Therefore genetic factors might be important in the development of sequential bilateral testicular cancers.

An estimate of the heritable fraction of childhood cancer

We have reviewed the records of the 16,564 cases of childhood cancer diagnosed from 1971 to 1983 which were reported to the National Registry of Childhood Tumours in Great Britain for the presence of underlying genetic disease in order to estimate the proportion which results from inherited mutations. A genetic condition was listed for 509 patients, or 3.07% of the total number of tumours. The most frequently recorded diagnoses were: bilateral retinoblastoma (162 cases); Down syndrome (135); neurofibromatosis (90); hereditary Wilms' tumour (71); and tuberous sclerosis (20). The highest hereditary fractions at individual tumour sites were seen for: retinoblastoma (37.2%); kidney (7.2%); leukaemia (2.6%) and brain and spinal cord (2.0%). When information about family history from published reports was incorporated into the figures calculated from Registry data the total genetic fraction was estimated to be 4.2%. We conclude that there is a clear genetic basis for a small minority of the cancers of childhood, but ethnic variation and the lack of known environmental determinants suggest that the total influence of heredity may be higher.

Familial testicular cancer in five members of a cancer-prone kindred

Of a family of 13 siblings, four brothers have developed testicular neoplasms, one embryonal cell carcinoma and three testicular seminomas. A first cousin once removed on their mother's side of the family (fourth-degree relative) has developed an embryonal carcinoma. After treatment they are all alive and well. Their mother is a dizygous twin and one of ten siblings. Multiple other cancers have been diagnosed among her siblings and their offspring including breast carcinoma at age 30 years in monozygous twin nieces. Associated urogenital abnormalities, concordance of age, and discordance of pathology in the five males with testicular cancer is discussed. Further identification and reporting of this risk factor is encouraged.

Familial testicular cancer: report of six cases and review of the literature

The cause of testicular cancer, like most other cancers, is unknown. Certain risk factors such as cryptorchidism, carcinoma in situ, and a preceding contralateral testicular germ cell neoplasm are known to predispose a person to the subsequent development of a testicular malignant lesion. Familial testicular cancer has been debated as a potential and possibly independent risk factor. Evidence in favor of such a hypothesis, based on various genetic studies reported during the past few decades, is reviewed. We add to the existing literature our experience with six cases of familial testicular cancer encountered during a 10-year period, consisting of four father-and-son pairs, one pair of nontwin brothers, and a 23-year-old man who had a maternal uncle with a history of testicular cancer.

Are germ cell tumors part of the Li-Fraumeni cancer family syndrome?

The occurrence of six cases of germ cell tumors, five testicular and one ovarian, in relatives of children with bone or soft tissue sarcomas is described. It is proposed that germ cell tumors may be an uncommon manifestation of the genetic predisposition to cancer that exists in the Li-Fraumeni cancer family syndrome.

Testicular cancer in three brothers

Three of four brothers in a family were diagnosed to have testicular tumour. All brothers were in their twenties at diagnosis and all had malignant teratoma, intermediate. One of the brothers, in addition, had a seminoma on the same side as the teratoma. The cases were unusual as there was no family history of cancer and no congenital abnormalities, such as cryptorchidism. Chromosomal analysis and HLA typing did not help in elucidating the cause of this rare familial occurrence of testicular tumour.

Increased breakage of chromosome 1 in lymphocytes of patients with testicular cancer after bleomycin treatment in vitro

Chromosome damage in vitro after bleomycin treatment during the late S and G2 phases of the cell cycle was studied in the peripheral lymphocytes of 19 untreated patients with primary testicular tumours and 22 age-matched healthy men with no excess of cancer incidence in the families. The occurrence of spontaneous chromosome aberrations was not shown to be different in the studied groups. However, in the lymphocytes treated with bleomycin, cancer patients exhibited higher numbers of break events per cell (1.06 versus 0.67, P less than 0.01) and increased frequency of cells with aberrations (55.0 versus 43.0, P less than 0.05) than control group. Aberrant cells of cancer patients had more aberrations than cells of the control sample (1.79 versus 1.53, P less than 0.01). The frequency of chromosome 1 aberrations, often encountered in cancer cells of testicular and other solid tumours, was significantly higher in lymphocytes of patients with testicular cancer (15.0 versus 8.4%, P less than 0.0001), the long arm of this chromosome being predominantly affected (12.0 versus 6.3%, P less than 0.0001). These results support the view that a genome disposed to testicular cancer is less effective in the ability to repair non-specific DNA damage in this region, more susceptible to damage, or both.

HLA association of testicular seminoma

Clinical and epidemiological studies suggest that genetic factors may be involved in the etiology and pathogenesis of testicular germ-cell tumors (GCTs). Previous HLA studies have tried to support the concept of genetic anticipation of GCTs, however, the results obtained have been inconsistent. The reasons for the divergent results are mainly statistical problems, i.e., small patient populations, high numbers of antigens tested, and inhomogeneous study populations. In the present retrospective study, 52 patients with histologically pure seminoma were typed for their HLA-A, B, C, and DR antigens. Only BW41 proved to be significantly increased in frequency after correction for the number of antigens tested (chi Q = 12.73; P = 0.0005). HLA-DR1 was shown to be decreased, however, the difference was not significant. Regarding metastatic seminoma alone, there was a trend towards an increase of A29, BW41, and DR7. Our study gives only weak evidence for the participation of genetic factors in the pathogenesis of seminoma. The statistical trend of HLA association observed in metastatic seminoma deserves further concern as does the question of whether MHC class II antigens are also involved in the pathogenesis of testicular seminoma.