Trends in the incidence of testicular germ cell tumors in the United States

Management and outcome of bilateral testicular germ cell tumors: a 25-year single center experience

OBJECTIVES

To analyze risk factors, management, histology, and outcome of bilateral testicular germ cell tumors (TGCT) based on a 25-year single center experience.

METHODS

Out of 612 patients treated for TGCT between 1982 and 2007, 17 (3%) were found to have bilateral disease. Data of these patients were reviewed and analyzed.

RESULTS

Eleven patients (65%) were identified with metachronous and 6 (35%) with synchronous bilateral TGCT. One patient had a cryptorchism in childhood. Patients with metachronous bilateral disease presented at lower stages than those with synchronous bilateral disease (stage I: 82% vs 33%, P = 0.02). In metachronous bilateral TGCT, the interval between the tumors ranged from 4 months to 25 years with a median of 47 months. The risk of developing a TGCT in the contralateral testicle was 26-fold higher than the a-priori risk for a healthy individual to develop TGCT. Overall, 74% of the bilateral tumors were seminomas and >50% of the patients had similar histology on both sides. After a median follow up of 121 months for patients with synchronous and 95 months for patients with metachronous bilateral TGCT, all patients were alive with no evidence of disease.

CONCLUSIONS

Most bilateral TGCT develop metachronously and are seminomas. Although patients with synchronous bilateral disease present at higher stages, both synchronous and metachronous bilateral TGCT carry a similar, excellent prognosis. Patients with unilateral TGCT require careful long-term monitoring of the remaining testicle due to a 26-fold increased risk of contralateral disease and a potentially long risk interval of up to 25 years.

Genes, chromosomes and the development of testicular germ cell tumors of adolescents and adults

Testicular germ cell tumors (TGCTs) of adults and adolescents are thought to be derived from primordial germ cells or gonocytes. TGCTs develop postpuberty from precursor lesions known as intratubular germ cell neoplasia undifferentiated. The tumors can be divided into two groups based on their histology and clinical behavior; seminomas resemble primordial germ cells or gonocytes and nonseminomas resemble embryonic or extraembryonic tissues at various stages of differentiation. The most undifferentiated form of nonseminoma, embryonal carcinoma, resembles embryonic stem cells in terms of morphology and expression profiling, both mRNAs and microRNAs. Evidence supports both environmental factors and genetic predisposition underlying the development of TGCTs. Various models of development have been proposed and are discussed. In TGCTs, gain of material from the short arm of chromosome 12 is invariable: genes from this region include the proto-oncogene KRAS, which has activating mutations in approximately 10% of tumors or is frequently overexpressed. A number of different approaches to increase the understanding of the development and progression of TGCTs have highlighted the involvement of KIT, RAS/RAF/MAPK, STAT, and PI3K/AKT signaling. We review the role of these signaling pathways in this process and the potential influence of environmental factors in the development of TGCTs.

Trends in testicular germ cell cancer incidence in Australia

OBJECTIVE

Although increasing incidence of testicular germ cell cancer has been reported in many developed nations, national estimates for Australia, with histological differentiation, are not currently available.

METHODS

Using data from all state and territory population-based cancer registries in Australia, this paper reports on incidence trends for seminomas and non-seminomas in Australia between 1982 and 2004 using Joinpoint and Age-Period-Cohort models.

RESULTS

Of the 10,528 testicular germ cell cancers diagnosed during this period, 6086 (58%) were seminomas. Incidence rates have increased (2.6% per year) in Australia since 1982, with the effect stronger among seminomas (3.4% per year) rather than non-seminomas (1.4% per year). There was a strong age effect evident for both subtypes, peaking in the 25-29 year age group for non-seminomas and the 30-34 year age group for seminomas. Non-seminoma rates reflected a significant birth cohort effect, following a U-shaped pattern with the lowest risk among the 1,945 birth cohort.

CONCLUSIONS

The differential trends observed for Australia for seminomas and non-seminomas are consistent with those reported for the United States, but slightly different to those reported for Europe. The trends may be at least partly due to changes over time in the prevalence of etiologic or protective factors around the time of birth.

Declining trends in conception rates in recent birth cohorts of native Danish women: a possible role of deteriorating male reproductive health

Recent findings of poor semen quality among at least 20% of normal young men in Denmark prompted us to use unique Danish registers on births and induced abortions to evaluate a possible effect of the poor male fecundity on pregnancy rates among their presumed partners--the younger cohorts of women. We have analysed data from the Danish birth and abortion registries as well as the Danish registry for assisted reproduction (ART) and defined a total natural conception rate (TNCR), which is equal to fertility rate plus induced abortion rate minus ART conception rate. A unique personal identification number allowed the linkage of these databases. Our database included 706,270 native Danish women born between 1960 and 1980. We used projections to estimate the fertility of the later cohorts of women who had not yet finished their reproduction. We found that younger cohorts had progressively lower TNCR and that in terms of their total fertility rate, the declining TNCR is compensated by an increasing use of ART. Our hypothesis of an ongoing birth cohort-related decline in fecundity was also supported by our finding of increasing and substantial use of ART in the management of infertility of relatively young couples in the later cohorts. Furthermore, the lower rates of induced abortion among the younger birth cohorts, often viewed as a success of health education programs, may not be fully explained by improved use of contraception. It seems more likely that decreased fecundity because of widespread poor semen quality among younger cohorts of otherwise normal men may explain some of the observed decline in conception rates. This may imply increasing reproductive health problems and lower fertility in the future, which is difficult to reverse in the short term. The current and projected widespread use of ART in Denmark may be a sign of such an emerging public health problem.

Testicular cancer: marked birth cohort effects on incidence and a decline in mortality in southern Netherlands since 1970

The aim of our study was to interpret the changing incidence, and to describe the mortality of patients with testicular cancer in the south of the Netherlands between 1970 and 2004. On the basis of data from the Eindhoven Cancer Registry and Statistics Netherlands, 5-year moving average standardised incidence and mortality rates were calculated. An age-period-cohort (APC) Poisson regression analysis was performed to disentangle time and birth cohort effects on incidence. The incidence rate remained stable for all ages at about 3 per 100,000 person-years until 1989 but increased annually thereafter by 4% to 6 in 2004. This increase can almost completely be attributed to an increase in localised tumours. The largest increase was found for seminoma testicular cancer (TC) patients aged 35-39 and non-seminoma TC patients aged 20-24 years. Relatively more localised and tumours with lymph node metastases were detected in the later periods. APC analysis showed the best fit with an age-cohort model. An increase in incidence of TC was found for birth cohorts since 1950. The mortality rate dropped from 1.0 per 100,000 person-years in 1970 to 0.3 in 2005, with a steep annual decline of 12% in the period 1979-1986. In conclusion, the increase in incidence of TC was strongly correlated with birth cohorts since 1945. The increase in incidence is possibly caused by in utero or early life exposure to a yet unknown risk factor. There was a steep decline in mortality in the period 1979-1986.

The role of positron emission tomography in the evaluation of residual masses after chemotherapy for advanced stage seminoma

PURPOSE

Treatment in patients with seminoma who have residual or recurrent masses following chemotherapy is still a matter of debate. Surgical resection is currently the most common recommendation for masses greater than 3 cm, resulting in overtreatment in up to 70% of those affected. We analyzed the accuracy of preoperative positron emission tomography for predicting viable tumor residuals in patients with seminoma.

MATERIALS AND METHODS

In a prospective, multicenter trial computerized tomography and FDG (2-(F-18)-fluoro-2-deoxy-D-glucose) positron emission tomography were performed before surgical resection for residual or recurrent masses in 20 patients who had undergone chemotherapy for stage IIb, IIc or III seminoma. Histopathological findings were directly correlated with positron emission tomography results.

RESULTS

Of the patients 18 presented with residual masses and 2 had recurrent masses following chemotherapy. Histopathological assessment revealed viable tumor in 3 patients and benign lesions in 17. All patients with viable tumor were identified correctly by positron emission tomography. No false-negative results were observed but 9 patients had false-positive positron emission tomography results. This resulted in a negative predictive value of 1 (95% CI 0.63-1) and a positive predictive value of 0.25 (95% CI 0.05-0.57) for FDG-positron emission tomography in our patient cohort.

CONCLUSIONS

Our data indicate that FDG-positron emission tomography is capable of excluding viable disease in residual masses, even those exceeding 3 cm. Therefore, it may be considered an additional tool to improve patient counseling. However, the decision to perform surgical resection of the residual mass should not be based exclusively on a positive positron emission tomography image since false-positive results appear to be common.

A rare case of classic testicular seminoma in an 86-year-old shows similar proliferation rate as in younger men

We present a rare case of classic seminoma in an 86-year-old man. Combined mitotic count, the presence or absence of intravascular invasion, and the expression of PCNA, Ki67, and p53 were compared between this octogenarian and the tumors of four randomly selected standard younger men. These histologic features were chosen to compare the potential biologic activity of these tumors. The phenotype of classic seminomas in octogenarians seems to be the same as in younger men, and treatment paradigms should remain unchanged.

Subtype-specific incidence of testicular cancer in Germany: a pooled analysis of nine population-based cancer registries

Comparisons of incidence estimates of testicular cancer subtypes beyond seminoma and non-seminoma are virtually missing in the epidemiologic literature. We analysed incidence data from population-based German cancer registries to provide subtype-specific incidences of testicular cancer. We pooled data from nine cancer registries from 1998 to 2003. We estimated incidence and mortality time trends of West and East Germany. Incidence and mortality were standardized by the European standard population. The annual percentage incidence change from 1961 through 1989 was 4.9% in East Germany and 3.0% from 1970 through 2004 in Saarland. Incidence increases were the most pronounced among adolescents and young men aged 15-49 years. In 1998-2003, the seminoma incidence rate was 5.1 per 100,000; among non-seminomas, the rates were the highest for malignant teratoma (1.6 per 100,000), followed by embryonal carcinoma (1.2 per 100,000). Testicular lymphomas were rare (0.1 per 100,000). The incidence of testicular cancer among children aged 0-14 years was nearly constant from 1987 through 2004. Majority of these cancers were yolk sac tumours (0.1 per 100,000). In East and West Germany, rates of embryonal carcinoma in the early periods were considerably lower than the rates of malignant teratoma. In the most recent periods, rates of embryonal carcinoma became quite similar to the rates of malignant teratoma. The mortality decline started in West Germany roughly 12 years earlier than in East Germany. The later start of the mortality decline in East Germany may be because of a later introduction of platinum-based chemotherapy compared to West Germany.

Risk of testicular germ-cell tumours in relation to childhood physical activity

The US Servicemen's Testicular Tumor Environmental and Endocrine Determinants (STEED) case–control study of testicular germ-cell tumours (TGCTs) enrolled participants and their mothers in 2002–2005. Hours of sports or vigorous childhood physical activity per week were ascertained for three time periods; 1st–5th grades, 6th–8th grades and 9th–12th grades. Son- and mother-reports were analysed separately and included 539 control son–mother pairs and 499 case son–mother pairs. Odds ratios and 95% confidence intervals were produced. The analysis of the sons' responses found no relationship between childhood physical activity and TGCT, while the mothers' analysis found an inverse association, which was solely due to nonseminoma. Future studies should seek to validate responses further using recorded information sources such as school records.

Doubling of testicular cancer incidence rate over the last 20 years in southern France

In recent decades, testicular cancer incidence has considerably increased in a majority of industrialized countries. In France, short reports suggested that the testicular cancer incidence rate has also risen, especially in north-eastern regions. In Europe, geographical variation of incidence rates has been observed in Baltic countries and a clear birth cohort effect has been revealed. This study aimed to assess temporal trends in testicular cancer incidence in southern France. We examined incidence rates over a 20-year time period in a series of 506 consecutive cases of testicular cancer recorded from 1980 to 1999 in the Midi-Pyrenees region of France. Age, calendar period, and birth cohort effects were examined simultaneously using Poisson regression models. Our analysis found a significant rise in the overall incidence rate of testicular germ cell tumors from 1.27 to 3.04 per 100,000 between 1980-1984 and 1995-1999, an annual increase of 5.70%. These results, the first obtained in a large series in southern Europe, show a twofold increase in incidence rate of testicular cancer in the Midi-Pyrenees region, which is very similar to that observed in all European countries, more or less doubling in the last 20 years. Interestingly, this major jump and the apparent testicular cancer gradient between northern and southern Europe suggest considerable geographical heterogeneity in incidence, but low geographical variation in temporal trends.

Incidental testicular cancers that subsequently developed in oligozoospermic and azoospermic patients: report of three cases

OBJECTIVE

To examine whether infertile men with poor semen count subsequently developed testicular cancers and to describe their clinical presentation.

DESIGN

We reviewed 460 male patients with abnormal semen counts between 1989 and 2004.

SETTING

University hospital.

PATIENT(S)

Infertile men who developed testicular cancers after assisted reproductive technologies (ART).

INTERVENTION(S)

Description of patient characteristics: age at infertility, presentation, semen quality, and ART.

MAIN OUTCOME MEASURE(S)

The number of patients who subsequently developed testicular cancers and the period from ART to the development of clinical testicular cancers.

RESULT(S)

Of the 460 patients, 169 patients presented with mild oligozoospermia, 117 patients with severe oligozoospermia, and 174 patients with azoospermia. The follow-up periods were as follows: 1-192 months (median, 96.5 mo) for mild oligozoospermia, 1-156 months (median, 78.5 mo) for severe oligozoospermia, and 1-197 months (median, 99 mo) for azoospermia. We subsequently found three testicular cancers that had developed among severely oligozoospermic and azoospermic patients. The period from the claim of sterility to developing testicular cancers varied from 4 to 14 years (median, 9 y).

CONCLUSION(S)

These results indicate that severe semen abnormality may be a risk factor in developing testicular cancers. Self-examination of the testes could be used as an alternative or supplement to physical examination and testicular ultrasound as part of the infertility workup, even after ART.

Testicular cancer trends as 'whistle blowers' of testicular developmental problems in populations

Recently a worldwide rise in the incidence of testicular germ cell cancer (TGCC) has been repeatedly reported. The changing disease pattern may signal that other testicular problems may also be increasing. We have reviewed recent research progress, in particular evidence gathered in the Nordic countries, which shows strong associations between testicular cancer, undescended testis, hypospadias, poor testicular development and function, and male infertility. These studies have led us to suggest the existence of a testicular dysgenesis syndrome (TDS), of which TGCC, undescended testis, hypospadias/disorders of sex differentiation and male fertility problems may be symptoms with varying penetration. In spite of their fetal origin, most of the TDS symptoms, including TGCC and poor semen quality, can only be diagnosed in adulthood. Data from a Danish-Finnish research collaboration strongly suggest that trends in TGCC rates of a population may be 'whistle blowers' of other reproductive health problems. As cancer registries are often of excellent quality - in contrast to registries for congenital abnormalities - health authorities should consider an increase in TGCC as a warning that other reproductive health problems may also be rising.

Testis and prostate cancer incidence in ethnic groups in South East England

International variations in the incidence of testis and prostate cancer are well established. Data from the USA have also shown differences between White and Black men; however, there has been little work on ethnicity and cancer incidence in the UK, due to incomplete ethnicity information in cancer registries. The Hospital Episode Statistics (HES) dataset has more complete information on self-assigned ethnicity for inpatients of English NHS hospitals. Data on 194 590 male patients resident in South East England diagnosed with cancer between 1998 and 2003 were extracted from the Thames Cancer Registry (TCR). Of these, ethnicity information from HES was obtained for 123 507 (63%), ethnicity information from TCR was available for a further 5909 (3%), and no ethnicity was available for 65 174 (33%). Compared with 'All White' men, testis cancer incidence was significantly lower in Indian, Pakistani, Bangladeshi, Other Asian, Black Caribbean, Black African, Other Black and Chinese men. Prostate cancer incidence was significantly increased in Black Caribbean, Black African, Other Black, Indian, Pakistani, Mixed White and Black Caribbean and Mixed White and Black African groups compared with 'All White' men. Bangladeshi and Chinese men had a significantly decreased incidence of prostate cancer. The incidence of prostate cancer in Indian and Pakistani men showed convergence towards the rates in the white population, suggesting the existence of modifiable risk factors in these men. Most other variations in these data are consistent with international comparisons, and indicate that genetic variations in susceptibility are very influential.

An overview of testicular germ cell tumors

CONTEXT

More than 90% of testicular neoplasms originate from germ cells. Testicular germ cell tumors (GCTs) are a heterogeneous group of neoplasms with diverse histopathology and clinical behavior.

OBJECTIVE

To help the readers distinguish various subtypes of GCTs, to highlight the clinical manifestations and pathologic features of these tumors, and to review several newly developed immunohistochemical markers for GCTs.

DATA SOURCES

Review of the pertinent literature and our experience.

CONCLUSIONS

The etiology of GCTs is largely unknown. Cytogenetic studies suggest a different pathogenesis for each group of infantile/prepubertal GCTs, postpubertal GCTs, and spermatocytic seminoma. Unclassified intratubular germ cell neoplasia is the precursor of all GCTs, excluding spermatocytic seminoma and infantile/prepubertal GCTs. Seminoma, the most common GCT in adults, does not occur before 5 years of age. Spermatocytic seminoma, a tumor of elderly men, typically has an indolent clinical behavior, but rarely it undergoes sarcomatous transformation associated with an aggressive behavior. Embryonal carcinoma is the most common component in mixed GCTs. Eighty percent or more of embryonal carcinoma component and vascular invasion are recognized predictors of occult metastasis for clinical stage I mixed GCTs. Most patients with prepubertal yolk sac tumor, the most common pediatric GCT, have stage I disease at presentation. Most choriocarcinomas present with metastatic symptoms because of the propensity for rapid hematogenous dissemination. Teratomas in children regardless of maturity and dermoid cysts in adults are benign; in contrast, teratomas in adults have a malignant behavior. With appropriate therapy, the majority of testicular GCTs are curable.

Trends in testicular germ cell tumours by ethnic group in the United States

The incidence of testicular germ cell tumours (TGCT) has increased in white and black men in the United States. Little is known, however, about trends among men of other racial/ethnic groups. The current study sought to examine TGCT patterns among men of Asian/Pacific Islander/American Indian/ Alaska Native (API/AIAN) and Hispanic ancestries and to determine whether tumours in these groups are diagnosed at comparable stages and sizes to tumours in white and black men. TGCT incidence data and tumour characteristics were drawn from the Surveillance, Epidemiology and End Results registries for two time periods: 1973-2003 and 1992-2003. In 1973-2003, TGCT rates were significantly lower among black (rate ratio = 0.18, p < 0.001) and API/AIAN (rate ratio = 0.37, p < 0.001) men than among white men. Among white and API/AIAN men, rates increased over 60%, mainly prior to 1989-1993. Among black men, rates increased almost 40%, mainly after 1989-1993. Among white and API/AIAN men, increasing proportions of localized disease were diagnosed over time, while the opposite trend was seen among black men. In 1992-2003, TGCT incidence among Hispanic white men (3.46/100 000) was significantly lower than it was among non-Hispanic white men, but rates of both seminoma and non-seminoma increased. While the incidence of TGCT increased among all men, different patterns in the increase were evident. These data suggest that rates are increasing among Hispanic white men and black men, but are stabilizing among white men and API/AIAN men. The peak of the TGCT epidemic may have been reached in these latter groups.

Testis cancer

PURPOSE

We quantified the burden of testis cancer in the United States by identifying trends in its incidence, its treatment and the use of health care resources to estimate the economic impact of the disease.

MATERIALS AND METHODS

The analytical methods used to generate these results were described previously.

RESULTS

The overall incidence of testis cancer in the United States increased 46% between 1975 and 2001. During the same period the ratio of seminoma to nonseminoma increased and there were fewer men presenting with stage II and III tumors. Survival rates increased successively, attaining the current level of 95.9%. Treatment patterns changed and active surveillance increased as a primary treatment modality. Overall hospitalization rates for men with testis cancer decreased from 1.8/100,000 in 1994 and 1.4/100,000 in 2000. Care for white men shifted to the outpatient setting, which did not occur for black men. The estimated annual expenditure for testis cancer for privately insured individuals between ages 18 and 54 years was $6,236. National estimates of annual medical expenditures placed the total cost of treatment at $21.8 million in 2000, representing an increase of 10% over the total in 1994. Of men with testis cancer 16% missed work for treatment of the disease with an average of 8.4 total hours of work missed.

CONCLUSIONS

The cost of testis cancer is estimated at almost $21.8 million annually. It appears to be increasing with time despite a shift to active surveillance treatments and less hospitalization.

Salvage chemotherapy with high-dose carboplatin plus etoposide and autologous peripheral blood stem cell transplant in male pure choriocarcinoma: a retrospective analysis of 13 cases

Choriocarcinoma of testes is a very rare tumor with poor prognosis, usually presenting with high serum level of human chorionic gonadotropin (hCG>50,000 mIU/ml) and advanced hematogenous metastases. Data with salvage chemotherapy has been sparse, with few long-term survivors. Between April 1996 and October 2004, 184 patients with germ cell tumor were treated at Indiana University with salvage high-dose chemotherapy (HDCT) with autologous peripheral blood stem cell transplant. Thirteen had pure choriocarcinoma or choriocarcinoma syndrome (normal testes by palpation and ultrasound, normal serum alpha-fetoprotein, advanced hematogenous metastases and high level hCG). All patients had progressed following one or two lines of cisplatin combination therapy. HDCT regimen was carboplatin 700 mg/m(2) and etoposide 750 mg/m(2) intravenously given for 3 consecutive days. A second course was given after hematopoietic recovery, usually 3-4 weeks later. The median survival was 19 months (range 5-90). Six patients (46%) are alive and continuously disease free (cNED) at a median follow-up of 37 months (range 19-75). One additional patient who relapsed after HDCT and was treated with third line chemotherapy followed by two surgical resections of choriocarcinoma is currently alive NED at +90 months from HDCT. Long-term disease-free survival and potential cure is possible with HDCT in choriocarcinoma patients that progressed after standard cisplatin combination therapy.

Management of Low-Stage Testicular Seminoma

Testicular seminoma represents a modern model of a multidisciplinary approach to a curable neoplasm. Surgeons, radiation oncologists, and medical oncologists play an important role in disease detection, diagnosis, treatment, and follow-up. This article focuses on the management of men who have early-stage seminoma, which represents stage I and IIa (minimal retroperitoneal spread). In stage I disease, the major controversies continue to revolve around surveillance versus adjuvant treatment and more recently adjuvant radiotherapy or carboplatin-based chemotherapy. Focus on long-term complications, such as cardiovascular disease, gastrointestinal disease, and secondary cancers, has led to the concept of increased surveillance with therapy for those who relapse. Radiation therapy remains the mainstay of therapy for patients who have stage IIa disease.

Testicular Cancer Variations in Time and Space in Europe

OBJECTIVES

Testicular cancer (TC) is the most common malignancy in young men. A review of all published articles on TC incidence revealed an increased incidence in Northern and Central Europe. We extended the analysis to the whole of Europe by using all data available, notably from registries.

METHODS

We performed a PubMed search and selected articles dealing with TC incidence. We obtained additional information from data of European registries through the eight volumes of the Cancer Incidence in Five Continents, IARC Scientific Publications.

RESULTS

Since the Second World War, TC incidence has been increasing in nearly all European countries. It has doubled in several countries, including France, since 1970. We observed that the increase followed a gradient: the highest rate is centred in Denmark and Germany, and decreases progressively in a centrifugal manner.

CONCLUSIONS

TC incidence is increasing throughout Europe, but wide discrepancies exist between the different countries. The reasons for such a phenomenon are still unclear although environmental factors are strongly suspected, which could have an impact on male fertility. From a public health perspective, further research using cases collected through national and regional population-based registers and case-control studies must be strongly encouraged.

Incidence and survival for testicular germ cell tumor in young males: a report from the Northern Region Young Person's Malignant Disease Registry, United Kingdom

The incidence of testicular cancer has increased markedly in most developed countries, although the reasons for this are unclear. In this study, 253 patients with testicular cancer diagnosed younger than 25 years from 1968-1999 were identified from the Northern Region Young Persons' Malignant Disease Registry. The age-standardized incidence rate increased from 0.93 in 1968-1978 to 1.60 per 100,000 in 1990-1999. The increase in incidence was confined to those patients >15 years old, with the rate in younger children remaining very low. The 5-year survival increased significantly from 46% (95% confidence interval [CI] 33% to 58%) to 92% (95% CI 85% to 96%) during 1968-1999 and was significantly higher for seminoma than nonseminoma, 91% (95% CI 78% to 96%) and 77% (95% CI 70% to 82%), respectively. Although increased surveillance and public health campaigns designed to raise awareness of the disease and the advantages of self-examination should continue, further research is required into the etiology of this relatively common cancer among young males.

Maternal hormone levels and perinatal characteristics: implications for testicular cancer

PURPOSE

It was hypothesized that the risk for testicular germ cell tumors (TGCTs) is associated with maternal hormone levels. To examine the hypothesis, some studies used perinatal factors as surrogates for hormone levels. To determine the validity of this assumption, hormone-perinatal factor relationships were examined in the Collaborative Perinatal Project.

METHODS

Maternal estradiol, estriol, and testosterone levels in first- and third-trimester serum samples were correlated with perinatal factors in 300 mothers representative of populations at high (white Americans) or low (black Americans) risk for TGCT.

RESULTS

For white participants, testosterone levels were associated negatively with maternal height (p < 0.01) and age (p = 0.02) and positively with maternal weight (p = 0.02) and body mass index (BMI; p < 0.01), whereas estradiol levels were associated negatively with height (p = 0.03) and positively with son's birth weight (p = 0.04). For black participants, estriol levels were associated negatively with maternal weight (p = 0.01), BMI (p = 0.02), and gestational age p < 0.01) and positively with son's birth weight (p < 0.01), length (p = 0.04), and head circumference (p = 0.03).

CONCLUSIONS

These findings indicate that use of perinatal characteristics as surrogates for hormone levels should be limited to a specific ethnic group. For white men, previously reported associations of TGCT with maternal weight and age may be caused by lower maternal testosterone levels.

Testicular cancer and male infertility

PURPOSE OF REVIEW

Testicular cancer and infertility affect a similar age group of patients and have common biologic, epidemiologic, and environmental backgrounds. In this review, we provide current literature on links between infertility and testicular cancer, and new developments in the management of testicular cancer aimed at improving quality of life in men with testicular cancer.

RECENT FINDINGS

In-utero environmental exposure to endocrine disruptors modulates the genetically determined fate of primitive gonad and results in testicular dysgenesis syndrome, which may result in infertility and testicular cancer. Excellent response of testicular cancer to radiation and chemotherapy results in over 90% of survival and quality of life--fertility and sexual function--is of significant concern to patients and clinicians. The testicular-sparing management of testicular masses emerges as a sound alternative to radical orchiectomy and allows for preservation of spermatogenesis and hormonal function, and at the same time achieving similar survival rates. Secondary malignancies, pulmonary, and cardiovascular complications are recognized as late complications of treatment for testicular cancer.

SUMMARY

Better understanding of common mechanisms involved in infertility and testicular cancer, and scientifically driven evidence-based treatment options should improve quality of life in young men faced with this potentially life-threatening disease.

Novel epigenetically deregulated genes in testicular cancer include homeobox genes and SCGB3A1 (HIN-1)

Testicular germ cell tumours (TGCTs) are classified into two main histological subgroups: seminomas and non-seminomas. The latter comprise several subtypes: embryonal carcinomas, yolk sac tumours, choriocarcinomas, and teratomas. These embryonal and extra-embryonal-like differentiation lineages represent a caricature of early normal development, and inactivation of gene expression through promoter hypermethylation may therefore be of particular importance in germ cell tumourigenesis. The promoter methylation status of ten candidate genes-CDH13, DLX6, EMX2, HOXA9, HOXB5, MSX1, MSX2, RASSF1A, RUNX3, and SCGB3A1 (alias HIN-1)-was assessed by methylation-specific PCR in seven intratubular germ cell neoplasias and 55 primary TGCTs. Furthermore, by a discovery-based global approach, comparing cDNA microarray expression profiles of two germ cell tumour cell lines before and after treatment with the demethylating agent 5-aza-2'-deoxycytidine, a gene list of potentially epigenetic targets was identified, from which CGGBP1, CGRRF1, SMARCC2, SORBS1, and XPA were analysed further. Overall, the non-seminomas were significantly more often methylated than were seminomas (p < 0.001). The three most frequently methylated genes among this subtype were SCGB3A1 (54%), RASSF1A (29%), and HOXA9 (26%). CDH13 and HOXB5 were methylated at low frequencies (10-15%), and EMX2, MSX1, RUNX3, SORBS1, and XPA only rarely (<10%). In conclusion, this study has identified several novel epigenetically deregulated target genes in TGCT development, including homeobox genes and SCGB3A1, suggesting that epigenetic inactivation of key genes in normal development also has an important role in TGCTs.

Expression and function of protein phosphatase PP2A in malignant testicular germ cell tumours

Testicular germ cell tumours (TGCT) represent the most common malignancy in young males. We reported previously that two prototype members of the mitogen-activated protein kinase (MAPK) family, the MAPK ERK kinase (MEK) and extracellular signal-regulated kinase (ERK), are inactive in malignant testicular germ cells and become active after drug stimulation, leading to apoptosis of tumour cells. In this study, we asked whether the protein phosphatase PP2A, a known inhibitor of the MEK-ERK pathway, participates in the proliferation and/or apoptosis of primary TGCT (n = 48) as well as two TGCT cell lines (NTERA and NCCIT). Quantitative RT-PCR, immunohistochemistry, western blot analyses and phosphatase assay indicate that primary TGCT as well as TGCT cell lines express PP2A and that PP2A is active in TGCT cell lines. The inhibition of PP2A by application of two PP2A inhibitors, cantharidic acid (CA) and okadaic acid (OA), results in a significant increase in caspase-3-mediated apoptosis of TGCT cell lines. Thereby, PP2A inhibition was accompanied by phosphorylation and activation of MEK and ERK. Functional assays using the MEK inhibitor PD98059 demonstrated that the phosphorylation of MEK and ERK was required for the induction of caspase-3-mediated apoptosis of malignant germ cells. Thus, our data suggest that inhibition of PP2A mediates its apoptosis-inducing effect on TGCT through activation of the MEK-ERK signalling pathway that leads to caspase-3-mediated apoptosis of tumour cells. In addition our results support previous observations that PP2A exerts an anti-apoptotic effect on malignant tumour cells.

Testicular cancer mortality in the Americas, 1980–2003

BACKGROUND

Testicular cancer is generally curable if appropriate treatment is given. Data and statistics on testicular cancer mortality over the last decades are available from the US and Canada, but are more difficult to find, in a standard and comparable format, for Central and South American countries. The objective of the study was to compare death rates and trends over the 1980-2003 period in all the American countries that provide data.

METHODS

Overall and 20 to 44 years age-standardized (world population) mortality rates from testicular cancer, derived from the World Health Organization (WHO) database, are presented for the most recent available calendar years in 10 American countries. Trends in mortality for selected countries of the Americas are also given over the period 1980-2003.

RESULTS

In the early 1980s the highest testicular cancer mortality rates were observed in Chile (1.7/100,000 at all ages, 3.6/100,000 at 20-44 years) and Argentina (0.9/100,000 at all ages, 1.7/100,000 at 20-44 years), as compared with 0.4/100,000 for all ages and 0.6/100,000 at 20 to 44 years in Canada, and 0.3/100,000 for all ages and 0.7/100,000 at 20 to 44 years in the US. In 2001-2003, testicular cancer mortality had fallen to 0.2/100,000 in men aged 20 to 44 years in Canada, and to 0.4/100,000 in the US. Conversely, rates were still 1.6/100,000 in Argentina, 2.2/100,000 in Chile and 1.2/100,000 in Mexico, and were around 0.5-0.6/100,000 in most other Latin American countries that provide data.

CONCLUSIONS

Mortality from testicular cancer in (young) men remains exceedingly high in most Latin American countries. Urgent intervention is required to provide treatment (essentially modern integrated platinum-based chemotherapy) for this largely curable neoplasm in young men.

Evidence-based guidelines for following stage 1 seminoma

BACKGROUND

The authors developed evidence-based guidelines for a follow-up schedule after orchiectomy for stage 1 seminoma. Required investigations, frequency of assessment, overall duration of follow-up, and management strategies were identified.

METHODS

A systematic review of the literature was performed of prospective studies in stage 1 seminoma. Studies published after 1980 were considered eligible for inclusion. Data extracted included relapse-free rates, number of patients at risk, and relapse locations. Five strategies were identified: Surveillance, Extended-Field Radiotherapy, Para-aortic Radiotherapy, and either 1 or 2 cycles of Carboplatin Chemotherapy. For each strategy, Kaplan-Meier relapse-free estimates were used to calculate weighted-mean cumulative hazards of relapse over time. These were used to calculate semiannual weighted-mean relapse hazards.

RESULTS

Seventeen prospective studies with a total of 5561 patients were identified. Actuarial data on relapse was available in 5013 (90.1%) patients, and 92.9% of all relapses had location data reported. Annual hazard rates for relapse were determined.

CONCLUSIONS

Evidence-based recommendations for follow-up frequency based on risk of relapse were formulated. The authors suggested 3 times per year when the risk is >5%, 2 times per year when the risk is 1% to 5%, and annually until the risk is <0.3%. Investigations should reflect location(s) at risk of relapse and include computed tomography of the abdomen and pelvis for surveillance and adjuvant carboplatin, whereas for para-aortic radiotherapy, pelvic computed tomography alone is required. These recommendations offer the possibility of maximal patient convenience and optimal healthcare resource allocation without compromising disease control.

Treatment Options, Prognostic Factors and Selection of Treatment in Stage I Seminoma

Treatment options in patients with stage I seminoma include radiotherapy (RT), surveillance, and adjuvant chemotherapy. This patient population has virtually a 100% cure rate whichever approach is taken. While adjuvant retroperitoneal RT has been the standard of care for the past 50-60 years, there is increasingly persuasive data that adjuvant RT in this setting is associated with a small but definite increased risk of second malignancy and cardiovascular death. The long-term data from surveillance series have documented the safety of this approach, and it is now accepted that a policy of surveillance is the optimal management approach. This gives a relapse rate of 15%, and most patients can be successfully salvaged with RT. Second relapse after salvage RT occurs in a small proportion of cases, and these patients are cured with chemotherapy. Adjuvant chemotherapy using carboplatin has been investigated as an alternative strategy but has not lived up to its initial promise. If used, then 2 courses of treatment should probably be given. It must be remembered that 80-85% of patients with testicular seminoma require no treatment after orchiectomy, and the long-term side effects of any adjuvant treatment approach must be carefully considered.

Do testicular seminoma and nonseminoma share the same etiology? Evidence from an age-period-cohort analysis of incidence trends in eight European countries

The incidence of the two main clinical subentities of testicular germ cell cancer (seminoma and nonseminoma) is increasing throughout Europe. Most studies have revealed little variation in risk factors between the two subtypes. This study compared generation-specific trends in eight European countries, hypothesizing that similar temporal pattern by birth cohort implied that seminoma and nonseminoma had a largely comparable etiology. The results are presented using the age-period-cohort model and the nonidentifiability problem highlighted by partitioning the age, period, and cohort effects in terms of their linear and curvature component parts, assuming a priori that cohort effects predominated. Despite uniform overall increases by calendar period, declining rates of nonseminoma but not pure seminoma were observed in the majority of countries during the 1990s. The subtype trends were, however, largely analogous on a birth cohort scale. Notable observations were a decline in rates of both subtypes among recent birth cohorts in Switzerland and a short-term wartime effect in several countries, involving an attenuation of increasing risk of both subtypes in men born in 1940 to 1945. Departures from the steady increases in testicular cancer over time were likely to occur for nonseminomas some years ahead of seminoma on a period scale. The importance of birth cohort coincided with the view that given a short time interval of susceptibility to exposures earlier in life and a biologically constant time to diagnosis, all temporal changes in rate-limiting exposures should appear as generational effects. Trends in seminoma and nonseminoma conform to largely the same temporal patterns on this scale, implying that they share important etiologic factors.

Testicular germ cell tumours in Iceland

The purpose of this study was to examine the pathology of all germ cell tumours of the testis diagnosed in Iceland 1955-2002. A total of 214 patients were included in the study. The current age-standardized incidence was found to be 6.1 per 100,000 and had increased almost fourfold during the study period. Seminoma was diagnosed in 55% of cases. Non-seminomas were diagnosed in 45%, and these were further classified as mixed germ cell tumours (33%), embryonal carcinoma (8%), teratoma (3%), and yolk sac tumour (n=1). The mean age at diagnosis was significantly higher for the seminomas than the non-seminomas (38 years versus 29 years) (p<0.001) and the non-seminomas were diagnosed at a significantly higher stage than the seminomas (p<0.001). Thus, in seminoma patients the tumour was localized to the testis (stage I) in 81% of cases, in 17% of patients the tumour had spread to the lymph nodes (stage II or III), and only 2% had extranodal metastasis at diagnosis (stage IV). In contrast, in the non-seminoma patients, the tumours were found to be stage I in 56%, stage II or III in 24%, and stage IV in 20% of cases. No significant difference in staging was found between non-seminoma subtypes. Identification of necrosis or vascular invasion was significantly associated with metastatic disease at diagnosis (p=0.002). During the study period a significant increase in stage I tumours was found as well as a decrease in the size of the tumours.

Adolescent Milk Fat and Galactose Consumption and Testicular Germ Cell Cancer

Recent case-control studies suggested that dairy product consumption is an important risk factor for testicular cancer. We examined the association between consumption of dairy products, especially milk, milk fat, and galactose, and testicular cancer in a population-based case-control study including 269 case and 797 controls (response proportions of 76% and 46%, respectively). Dietary history was assessed by food frequency questions for the index persons and through their mothers including diet 1 year before interview and diet at age 17 years. We used conditional logistic regression to calculate odds ratios as estimates of the relative risk (RR), 95% confidence intervals (95% CI), and to control for social status and height. The RR of testicular cancer was 1.37 (95% CI, 1.12-1.68) per additional 20 servings of milk per month (each 200 mL) in adolescence. This elevated overall risk was mainly due to an increased risk for seminoma (RR, 1.66; 95% CI, 1.30-2.12) per additional 20 milk servings per month. The RR for seminoma was 1.30 (95% CI, 1.15-1.48) for each additional 200 g milk fat per month and was 2.01 (95% CI, 1.41-2.86) for each additional 200 g galactose per month during adolescence. Our results suggest that milk fat and/or galactose may explain the association between milk and dairy product consumption and seminomatous testicular cancer.

Maternal Smoking and Testicular Germ Cell Tumors

Testicular germ cell tumors (TGCT) are the most common cancer among men ages 15 to 35 years in the United States. The well-established TGCT risk factors cryptorchism, prior diagnosis of TGCT, and family history of testicular cancer indicate that exposures in early life and/or in the familial setting may be critical to determining risk. Previous reports of familial clustering of lung cancer in mothers and testicular cancers in sons suggest that passive smoking in childhood may be such an exposure. To clarify the relationship of passive smoking exposure to TGCT risk, data from 754 cases and 928 controls enrolled in the Servicemen's Testicular Tumor Environmental and Endocrine Determinants study were analyzed. Data from 1,086 mothers of the cases and controls were also examined. Overall, there was no relationship between maternal [odds ratio (OR), 1.1; 95% confidence interval (95% CI), 0.9-1.3] or paternal smoking (OR, 1.0; 95% CI, 0.8-1.3) and TGCT risk. Although living with a non-parent smoker was marginally related to risk (OR, 1.4; 95% CI, 1.0-2.1), there was no relationship with number of smokers, amount smoked, or duration of smoking. Responses from both case-control participants and mothers also revealed no relationship between either maternal smoking while pregnant or while breast-feeding. Results did not differ by TGCT histology (seminoma, non-seminoma). These results do not support the hypothesis that passive smoking, either in utero or in childhood, is related to risk of TGCT. Other early life exposures, however, may explain the familial clustering of lung cancer in mothers and TGCT in sons.

Space-time clustering analyses of testicular cancer amongst 15-24-year-olds in Northern England

There has been speculation that environmental exposures may be involved in the aetiology of testicular cancer in adolescent boys and young men. Indirect evidence for this hypothesis would be provided by the finding of space-time clustering. To examine this we have looked for evidence of space-time clustering using data from a population-based cancer registry from Northern England. All cases of testicular cancer diagnosed in males aged 15-24 years during the period 1968-2002 were included in the study. Tests for space-time interactions between cases were applied with fixed thresholds of close in space and close in time. Addresses at birth and diagnosis were used in the analyses. To adjust for the effect of varying population density tests were repeated replacing fixed geographical distances with nearest neighbour thresholds. A total of 257 cases of testicular cancer were identified for analysis. Overall there was no evidence for space-time clustering. However, there was statistically significant space-time clustering for 15-19-year-old based on time of birth and place of diagnosis (p<0.001). The very limited finding of space-time clustering may provide tentative evidence for an environmental, or infectious component to aetiology. However, it may well be a chance finding. A larger study based on national data is required.

Testicular neoplasms. Evaluation of the experience during 25 years in a military hospital

INTRODUCTION

Testicular tumors are frequent in young adults, coinciding with incorporation to military service. The present study evaluates the tumor characteristics, time course and results obtained with the treatments used in our center for this type of neoplasms.

MATERIAL AND METHODS

A retrospective longitudinal study was conducted in a cohort of 98 patients with an average age of 28.6 years, subjected to orchiectomy for testicular tumors in our center between 1979 and 2004. Data were collected relating to patient age, tumor characteristics, the outcome of treatment, and the course of the disease.

RESULTS

The right testicle was affected in 61% (with significant differences versus the left side). The most common histological type corresponded to non-seminomatous germ cell tumors (NSGCTs) (65.3%), followed by pure seminomas (27.6%) and non-germinal cell tumors (NGCs) (7.1%). NSGCT was diagnosed at a significantly younger average age (23.2 years) than the other two tumor types. Stage I was the most frequent presentation (58%). Seminomas presented in stage I significantly more often (80%) than the others tumors. The data collected over the 25-year study period showed no significant variations in tumor characteristics. The log-rank test showed a significant difference in terms of patient survival according to the tumor cell line (p = 0.000) and stage (p = 0.000), except between stages I and II, where no significant differences were observed in terms of survival.

CONCLUSIONS

Non-seminomatous germ cell tumors (NSGCTs) are the most frequent testicular tumors in young adults. Most neoplasms are diagnosed in early stages, the prognosis being better in the case of seminomas and tumor stages I and II.

Incidence of testicular germ cell cancers in U.S. children: SEER program experience 1973 to 2000

OBJECTIVES

The incidence of testicular cancer in white adults in the United States increased during most of the last half of the 20th century, but information on trends in the occurrence of prepubertal testicular cancer is lacking. We analyzed a population-based cohort to determine whether the incidence trends of prepubertal testicular germ cell tumors have risen similarly to those seen in adult testicular tumors.

METHODS

We identified cases of histologically confirmed germ cell testicular cancer in boys aged 0 to 14 years, of all races, from 1973 to 2000, through the Surveillance, Epidemiology, and End Results program of the National Cancer Institute. The variables analyzed included age, race, tumor histologic type, and year of diagnosis.

RESULTS

A total of 131 cases of testicular germ cell cancer were diagnosed among boys of all races, with an overall incidence of 1.6 cases per 1 million person-years. Yolk sac tumor was the most common, followed by teratoma. Choriocarcinoma and seminoma were equally rare. Tumors were most common among whites during early infancy. No secular trends in incidence rates were identified.

CONCLUSIONS

Prepubertal testicular cancer is rare. All tumors were more common in whites. In contrast to adult testicular cancer, no clear trend over time was found for prepubertal tumors. Whatever the reasons for the increased incidence of testicular cancer over time in men, they do not seem to bear on the risk of testicular cancer in boys.

Role of MEK/ERK pathway in the MAD2-mediated cisplatin sensitivity in testicular germ cell tumour cells

Testicular germ cell tumour (TGCT) is the most common malignancy in young males. Although most TGCTs are sensitive to cisplatin-based chemotherapy, significant numbers of TGCT patients still relapse and die each year because of the development of resistance to cisplatin. Previously, we first reported that a key regulator of the mitotic checkpoint, mitotic arrest deficient-2 (MAD2), was a mediator of cisplatin sensitivity in human cancer cells. In this study, we investigated whether MAD2 played a role in cellular sensitivity to cisplatin in TGCT cells and the underlying molecular mechanisms responsible. Using 10 TGCT cell lines, we found that increased MAD2 expression was correlated with cellular sensitivity to cisplatin, which was associated with activation of the MEK pathway. Treatment of cells expressing high levels of MAD2 with an MEK inhibitor, U0126, led to cellular protection against cisplatin-induced apoptosis. Inactivation of MAD2 by transfecting a dominant-negative construct in TGCT cells with high levels of MAD2 resulted in the suppression of MEK pathway and resistance to cisplatin-induced cell death. These results support previous suggestion on the involvement of mitotic checkpoint in DNA damage response in human cancer cells and demonstrate a possible molecular mechanism responsible for the MAD2-mediated sensitivity to cisplatin in TGCT cells. Our results also suggest that downregulation of MAD2 may be an indicator for identification of TGCT cancer cells that are potentially resistant to cisplatin-based therapy.

Risk factors for cryptorchism among populations at differing risks of testicular cancer

BACKGROUND

Cryptorchism is strongly associated with the development of testicular germ cell tumours (TGCTs), possibly owing to a common aetiology. However, while TGCT incidence varies greatly between white and black men, little variability has been reported between the two groups in cryptorchism prevalence. This may suggest that cryptorchism risk factors differ by ethnicity.

METHODS

To examine this hypothesis, a prospective analysis was conducted among black and white participants in the US Collaborative Perinatal Project. White participants included 238 cryptorchid sons and 12,296 non-cryptorchid sons, while black participants included 188 cryptorchid sons and 11,942 non-cryptorchid sons.

RESULTS

While cryptorchism was significantly more common among white sons (1.90% vs 1.55%; P = 0.04), the difference was incompatible with the 5-fold difference in TGCT rates. The principal maternal risk factors among white sons were age (P = 0.03), hypertension/proteinuria (P = 0.006), and length of time to become pregnant (P = 0.055), while major maternal risk factors among black sons were age (P = 0.06), height (P = 0.007), weight (P = 0.06), and radiation exposure (P = 0.02). Only maternal height, however, had a different relationship with risk among black and white sons. Neonatal associations with risk (shorter gestational age, lower birthweight, shorter length) were similar in the two groups.

CONCLUSIONS

These results do not support the hypothesis that the risk factors for cryptorchism vary dramatically by ethnicity but may suggest that cryptorchism is not as closely linked to TGCT among black men as among white men.

Surveillance in stage I testicular seminoma

Treatment options in patients with stage I testicular seminoma include adjuvant radiotherapy (RT), surveillance, and adjuvant chemotherapy. RT was the treatment of choice for the past 50 years, but there has been increasing concern in the past decade regarding late complications. Surveillance, reserving treatment for patients who relapse, has been shown to be a safe and effective strategy. It allows >80% of patients to avoid any post-orchidectomy treatment and is the recommended approach for these patients. The possible role of adjuvant chemotherapy is currently being assessed in clinical trials and should not be used outside of a study setting.

Incidence and survival rates for female malignant germ cell tumors

OBJECTIVE

To evaluate 30-year, population-based trends in incidence and survival rates for malignant germ cell tumors originating within the female genital tract.

METHODS

Surveillance, Epidemiology, and End Results data were used to identify malignant germ cell tumors (1973-2002). Overall and 5-year incidence rates, estimated annual percentage change, and survival rates were calculated and compared by age at diagnosis, race, stage, and histology.

RESULTS

Of 1,262 cases, there were 414 (32.8%) dysgerminomas, 449 (35.6%) immature teratomas, 37 (2.9%) mature teratomas with malignant degeneration, and 362 (28.7%) mixed germ cell tumors. The 30-year, age-adjusted incidence rate per 100,000 women-years was 0.338, decreasing by 29.4% for dysgerminomas (P = .18) and by 31.5% for mixed germ cell tumors (P = .22). Other nonwhites had higher rates than whites and blacks, but dysgerminoma rates were higher in whites and other nonwhites than in blacks. Using the registries for expanded races, rates were higher for Asian/Pacific Islanders (P = .059) and Hispanics (P = .07). By age at diagnosis, 15-19 year olds had the highest rates and the only significant change in rates (37.5% increase, P = .008). The 5-year relative survival was 83.9%. Survival rates improved significantly over calendar time and varied by histologic subtype, race, stage of disease, and age at diagnosis.

CONCLUSION

Over the past 30 years, germ cell tumor incidence rates have declined in women and differ from rising trends reported for testicular tumors. Survival rates have improved but were lower for older women and for nondysgerminoma subtypes.

Testicular germ cell tumors

PURPOSE OF REVIEW

An overview of many of the preclinical and clinical developments in germ cell tumors over the past year is presented.

RECENT FINDINGS

Recent epidemiologic studies show changes in the ethnic incidence of germ cell tumors; in particular, African-Americans have seen an increase. Additionally, risk factors for the development of germ cell tumors continue to be identified. Work on the molecular pathways involved in the progression to malignancy continues to expand. First line treatment for the disease is highly effective. In an effort to limit unnecessary treatments and treatment-related toxicities, risk-adapted adjuvant therapies are being explored in early stage germ cell tumors. Identification of more effective second-line treatments for advanced relapsing and refractory disease remains a priority.

SUMMARY

Germ cell tumors are highly treatable, but significant challenges remain for recurrent and refractory disease. Recent studies on the molecular pathogenesis of germ cell tumors further highlight the complexity of the disease. As these processes are better understood, the therapeutic options will continue to evolve.

Trends in testicular cancer incidence in the Nordic countries, focusing on the recent decrease in Denmark

Testicular cancer is the most frequent malignancy among young men, and there have been steady increases in its incidence in most western countries for many decades. Recently, a decrease was seen in some countries, including Denmark. Here, we report recent trends in testicular cancer incidence in the Nordic countries. We address the hypothesis that the causal factors for testicular cancer in Denmark are related to birth cohort and that non-seminoma and seminoma tumours have a common aetiology. An overall increase in testicular cancer incidence was found in the Nordic countries, corresponding to increases with each consecutive birth cohort in each country. In Denmark, a decline in incidence was observed during the past 5 years, and men born around 1943 and around 1968 showed lower incidences than men born just before or just after these dates. These birth-cohort effects were seen both for seminoma and non-seminoma tumours. This descriptive study confirms the hypothesis that birth cohort has a major influence on the incidence pattern of testicular tumours and suggests that seminoma and non-seminoma have common aetiological factors.

Ethnic differences in occurrence of TDS - genetics and/or environment?

It has been hypothesized that poor semen quality, testis cancer, undescended testis and hypospadias are symptoms of one underlying entity, the so-called testicular dysgenesis syndrome (TDS). TDS was suggested to be a result of disruption of embryonal programming and gonadal development during foetal life and as aetiological factor, an impact of adverse environmental factors such as hormone disrupters, probably acting upon a susceptible genetic background, was suggested. Extensive studies considering the risk of TDS-related diseases in Denmark compared with Finland, showed higher sperm counts and lower risk of cryptorchidism and testicular cancer among Finns. However, when comparing these two populations, the question arises, to which degree this difference might be due to discrepancy in genetic background. A more obvious example of the impact of genetic factors on the risk of TDS concerns Afro-Americans having significantly lower incidence of testicular cancer when compared with Caucasians living in the USA. A yet unexplored scenario is a possible interaction between genetic and environmental/lifestyle-related factors, certain genotypes making individuals more susceptible to adverse exogenous exposures. Studying such interactions has biological, epidemiological and public health-related implications. It will help us to understand the background for the defects in male reproductive organs, facilitate proper design of epidemiological studies and add to identifying individuals susceptible to certain environmental and lifestyle-related hazards. Such 'susceptibility genes' need to be identified, those involved in the synthesis, action and metabolism of sex steroids being strong candidates.

The pluripotency homeobox gene NANOG is expressed in human germ cell tumors

BACKGROUND

The NANOG gene, a member of the homeobox family of DNA binding transcription factors, was recently identified in a screen for pluripotency-promoting genes. NANOG overexpression in murine embryonic stem cells is sufficient to maintain self-renewal and to block differentiation. The NANOG gene is located on human chromosome 12p13, a region frequently duplicated in human tumors of germ cell origin and in cultured human embryonic stem cells. Here we investigate the expression and gene copy number of NANOG in human germ cells and tumors of germ cell origin.

METHODS

Immunohistochemistry and quantitative polymerase chain reaction (QPCR) were used to examine the expression and gene copy number of the human NANOG gene in germ cell tumors.

RESULTS

NANOG protein was detected in germline stem cells (gonocytes) within the developing testis. Immunohistochemistry and quantitative real-time PCR analysis were used to demonstrate that NANOG is highly and specifically expressed in carcinoma in situ (CIS), embryonal carcinomas, and seminomas, but not in teratomas and yolk sac tumors.

CONCLUSIONS

NANOG expression in germline stem cells (gonocytes), CIS, embryonal carcinoma, and seminoma reveals a molecular and developmental link between germ cell tumors and the embryonic cells from which they arise. Identification of NANOG as a molecular marker of undifferentiated germ cell tumors provides a novel tool for identifying and classifying tumors of germ cell origin.