Morphology of testicular parenchyma adjacent to germ cell tumours. An interim report

Malignant germ cell tumors in men aged 50 years and over are associated with adverse pathologic features and higher stage at presentation

BACKGROUND

Germ cell tumors (GCT) are the most common malignancy in men in the third and fourth decades of life. The occurrence of malignant GCT in men aged 50 years or over is rare, and their histopathologic characteristics and outcome is insufficiently characterized in the medical literature. Hence, we report the histopathologic features and clinical outcome of malignant GCTs in men aged ≥50 years at our institution.

DESIGN

We performed a retrospective search of our database from 2005 to 2021 to identify men aged 50 years or older with malignant GCT. Cases of spermatocytic tumor were excluded. Clinical and histopathologic features of the tumors were reviewed.

RESULTS

Forty-seven cases were identified, showing a sharp decline in incidence over the age of 65. Thirty-nine (83 %) tumors were testicular while eight (17 %) were non-testicular in presentation. Cases included 26 (55 %) seminomas, 15 (32 %) non-seminoma/mixed malignant GCT, and 5 (11 %) regressed testicular germ cell tumors. The most common component in mixed malignant GCTs was embryonal carcinoma (77 %), followed by seminoma and yolk sac tumor (62 % each). Germ cell neoplasia in situ (GCNIS) accompanied 57 % of the cases. Aggressive pathologic features, including lymphovascular invasion, retroperitoneal/lymph node involvement and higher stage at presentation, were identified in a significant proportion of cases (36/47, 77 %). Clinical follow up showed six patients (14 %) died of disease-related causes.

CONCLUSION

Our findings expand and corroborate the previously reported data on malignant GCT in older men. Unique characteristics include tendency for higher stage at presentation with adverse pathologic features and more aggressive clinical course.

Histological Features of Sporadic and Familial Testicular Germ Cell Tumors Compared and Analysis of Age-Related Changes of Histology

Simple Summary

Testicular germ cell tumors (TGCT) are highly heritable, and earlier studies reported a higher prevalence of certain microscopic features in familial cases compared with sporadic cases. Reasoning by analogy relative to different causal genes for different histologic subtypes of familial kidney cancer, we searched for etiologically informative histopathology associations in familial testicular germ cell cancer. We conducted a detailed, blinded pathology review of familial and sporadic TGCT cases to investigate whether we could identify differences between these two patient subsets and to study the effect of age at diagnosis on histologic features in both groups combined. Our results show no specific histologic differences between familial and sporadic TGCTs. However, we observed histologic features that varied with age at diagnosis among the two groups combined. Thus, our results suggest that there are no histological differences between familial and sporadic TGCT that might identify genetically distinct disease subsets.

Abstract

This study aimed to compare histological features of familial and sporadic testicular germ cell tumors (TGCTs) and surrounding parenchyma, since discriminating features might be etiologically relevant and clinically useful. The study of parenchyma was prompted by reports claiming a higher prevalence of testicular microlithiasis in familial cases. Histological features of TGCTs and surrounding parenchyma of 296 sporadic and 305 familial cases were compared. For each case, one representative hematoxylin and eosin-stained slide was available. Slides were independently scored by two expert pathologists using a semi-quantitative data abstract. Discrepancies were resolved by consensus. A logistic regression model was used to assess the ability to discriminate between sporadic and familial GCT. The histological composition of a tumor, amount of lymphocytic infiltration, amount of germ cell neoplasia in situ (GCNIS), and presence of testicular microlithiasis (TM) did not discriminate between sporadic and familial GCT (area under the curve 0.56, 95%CI 0.51–0.61). Novel observations included increasing lymphocytic infiltration and decreasing GCNIS and TM with increasing age at diagnosis. The presence of tubules with infiltrating lymphocytes was mainly associated with pure seminomas and nonseminomas with a seminoma component. Among seminomas, tubules with infiltrating lymphocytes decreased with increasing age. No discernable differences between sporadic and familial TGCTs were found. The age-related changes in the tumors and surrounding parenchyma in these groups combined are consistent with a host response building up over time predominantly affecting seminomas, the seminoma-component of nonseminomas and GCNIS. TM may gradually dissolve with age. Our hypothesis that histological differences between sporadic and familial TGCT might identify genetically distinct disease subsets was not supported.

Clinicopathological Significance and Antitumor Effect of MPHOSPH1 in Testicular Germ Cell Tumor

MPHOSPH1, which is one of the kinesin superfamily proteins, has been reported to play an essential role in the carcinogenesis and progression of several kinds of cancers. MPHOSPH1 has also been suggested to be involved in STAT3 phosphorylation in hepatocellular carcinoma. However, the biological behavior of MPHOSPH1 in testicular germ cell tumors (TGCTs) is unclear at present. The purposes of this study were to investigate the correlation between the expression of MPHOSPH1 and clinicopathological factors and to examine the efficacy of MPHOSPH1 target therapy in TGCTs. We investigated 75 formalin-fixed paraffin-embedded TGCT samples, containing a total of 86 germ cell tumor components, by immunohistochemistry and 12 frozen samples by Western blotting. Moreover, we carried out in vitro studies to clarify the antitumor effect of MPHOSPH1 knockdown in embryonal carcinoma cell lines, NEC8 and NEC14, using small interference RNA (siRNA). A significantly high expression of MPHOSPH1 was recognized in embryonal carcinoma and yolk sac tumor components compared to the seminoma component (p<0.001, respectively). Clinically, non-seminoma cases are known to have worse prognosis than pure-seminoma cases. Interestingly, high MPHOSPH1 expression was associated with distant metastasis (p=0.001), and thus with advanced-stage disease in this study. High expression of MPHOSPH1 interacted with high expression of phosphorylated STAT3 (p=0.01). The in vitro experiments demonstrated that MPHOSPH1 interruption by siRNA resulted in a significant reduction of cell migration, invasion, proliferation and colony formation in both embryonal carcinoma cell lines (p<0.001, respectively). In conclusion, MPHOSPH1 may be a potential treatment option for TGCTs, and its expression may be a novel biomarker of poor prognosis.

Frequency and Markers of Precursor Lesions and Implications for the Pathogenesis of Testicular Germ Cell Tumors

BACKGROUND

The World Health Organization classification of urologic cancer 2016 describes 3 noninvasive precursor lesions for testicular germ cell tumor type II (TGCT) of young adults. Germ cell neoplasia in situ is the initial precursor lesion. Intratubular seminoma (ITSE), and intratubular embryonal carcinoma (ITEC) are 2 intermediate precursor lesions. Microinvasive testicular germ cell tumor (MGCT) is an invasive precursor lesion.

MATERIALS AND METHODS

We undertook a retrospective study of testes obtained using orchiectomy for TGCT and examined precursor lesions. The examinations included immunohistochemical staining of the precursor lesions for octamer-binding transcription factor 4 (OCT4), CD117, and CD30. We examined 63 consecutive and evaluable patients.

RESULTS

Of the patients, 44 had seminoma and 19 had a nonseminomatous TGCT. MGCT was more frequent than ITSE (P = .002; χ2 test). None of the testes had ITEC. Immunohistochemistry showed that 72 of 77 precursor lesions (93%) stained positive for OCT4 and CD117 and negative for CD30. The pattern represents a seminomatous immunophenotype. A meta-analysis of the published studies regarding precursor lesions included 1007 patients. Overall, the pooled rate of ITSE was 29% (95% confidence interval [CI], 18%-40%) and the pooled rate of MGCT was 21% (95% CI, 15%-27%).

CONCLUSION

MGCT is a frequent intermediate precursor lesion.

The World Health Organization 2016 classification of testicular germ cell tumours: a review and update from the International Society of Urological Pathology Testis Consultation Panel

Since the last World Health Organization (WHO) classification scheme for tumours of the urinary tract and male genital organs, there have been a number of advances in the understanding, classification, immunohistochemistry and genetics of testicular germ cell tumours. The updated 2016 draft classification was discussed at an International Society of Urological Pathology Consultation on Testicular and Penile Cancer. This review addresses the main updates to germ cell tumour classification. Major changes include a pathogenetically derived classification using germ cell neoplasia in situ (GCNIS) as a new name for the precursor lesion, and the distinction of prepubertal tumours (non-GCNIS-derived) from postpubertal-type tumours (GCNIS-derived), acknowledging the existence of rare benign prepubertal-type teratomas in the postpubertal testis. Spermatocytic tumour is adopted as a replacement for spermatocytic seminoma, to avoid potential confusion with the unrelated usual seminoma. The spectrum of trophoblastic tumours arising in the setting of testicular germ cell tumour continues to expand, to include epithelioid and placental site trophoblastic tumours analogous to those of the gynaecological tract. Currently, reporting of anaplasia (seminoma or spermatocytic tumour) or immaturity (teratoma) is not required, as these do not have demonstrable prognostic importance. In contrast, overgrowth of a teratomatous component (somatic-type malignancy) and sarcomatous change in spermatocytic tumour indicate more aggressive behaviour, and should be reported.

Significant calendar period deviations in testicular germ cell tumors indicate that postnatal exposures are etiologically relevant

PURPOSE

The current working model of type II testicular germ cell tumor (TGCT) pathogenesis states that carcinoma in situ arises during embryogenesis, is a necessary precursor, and always progresses to cancer. An implicit condition of this model is that only in utero exposures affect the development of TGCT in later life. In an age-period-cohort analysis, this working model contends an absence of calendar period deviations. We tested this contention using data from the SEER registries of the United States.

METHODS

We assessed age-period-cohort models of TGCTs, seminomas, and nonseminomas for the period 1973-2008. Analyses were restricted to whites diagnosed at ages 15-74 years. We tested whether calendar period deviations were significant in TGCT incidence trends adjusted for age deviations and cohort effects.

RESULTS

This analysis included 32,250 TGCTs (18,475 seminomas and 13,775 nonseminomas). Seminoma incidence trends have increased with an average annual percentage change in log-linear rates (net drift) of 1.25 %, relative to just 0.14 % for nonseminoma. In more recent time periods, TGCT incidence trends have plateaued and then undergone a slight decrease. Calendar period deviations were highly statistically significant in models of TGCT (p = 1.24(-9)) and seminoma (p = 3.99(-14)), after adjustment for age deviations and cohort effects; results for nonseminoma (p = 0.02) indicated that the effects of calendar period were much more muted.

CONCLUSION

Calendar period deviations play a significant role in incidence trends of TGCT, which indicates that postnatal exposures are etiologically relevant.

A pathologist's view on the testis biopsy

Aspects of the biopsy of the testis from the pathologist's point of view are discussed. Direct enzyme-histochemical staining for alkaline phosphatase (dAP) on frozen sections of biopsies taken during operation is a useful diagnostic tool to aid surgeons in testis-sparing surgery. Biopsy of the contralateral testis for the diagnosis of carcinoma in situ (CIS) in patients with a testicular germ cell tumour is not standard of care in most countries because of the high rate of negative biopsies. Based on risk factors for germ cell tumours, i.p. microlithiasis, a patient population is defined in which the rate of CIS in the contralateral biopsy is about 25%. It is reiterated that the diagnosis of CIS in testicular biopsies requires expertise, and should not be carried out without immunohistochemistry for markers for CIS. As OCT3/4 is increasingly used as marker, it is important to be aware that it may be false-negative in biopsies fixed in Bouin's or Stieve's fixative. Preliminary results are presented on a series of biopsies from cryptorchid testes in infants and children allowing the definition of morphological and immunohistochemical criteria for delayed maturation of gonocytes and pre-CIS.

Dissecting the molecular pathways of (testicular) germ cell tumour pathogenesis; from initiation to treatment-resistance

Human type II germ cell tumours (GCTs) originate from an embryonic germ cell, either as a primordial germ cell or gonocyte. This start determines the biological as well as clinical characteristics of this type of cancer, amongst others their totipotency as well as their overall (exceptional) sensitivity to DNA damaging agents. The histology of the precursor lesion, either carcinoma in situ or gonadoblastoma, depends on the level of testicularization (i.e. testis formation) of the gonad. The impact of either intrinsic (genetic) - and environmental factors involved in the pathogenesis is demonstrated by disorders of sex development as well as testicular dysgenesis syndrome as risk factors, including cryptorchidism, hypospadias and disturbed fertility as parameters. This knowledge allows identification of individuals at risk for development of this type of cancer, being a population of interest for screening. Factors known to regulate pluripotency during embryogenesis are proven to be of diagnostic value for type II GCTs, including OCT3/4, even applicable for non-invasive screening. In addition, presence of stem cell factor, also known as KITLG, allows distinction between delayed matured germ cells and the earliest stages of malignant transformation. This is of special interest because of the identified association between development of type II GCTs of the testis and a limited number of single nucleotide polymorphisms, including some likely related to KITL. Transition from the precursor lesion to an invasive cancer is associated with gain of the short arm of chromosome 12, in which multiple genes might be involved, including KRAS2 and possibly NANOG (pseudogenes). While most precursor lesions will progress to an invasive cancer, only a limited number of cancers will develop treatment resistance. Putative explanatory mechanisms are identified, including presence of microsatellite instability, BRAF mutations, apoptosis suppression and p21 sub-cellular localization. It remains to be investigated how these different pathways integrate to each other and how informative they are at the patient-individual level. Further understanding will allow development of more targeted treatment, which will benefit quality of life of these young cancer patients.

Zebrafish models of germ cell tumor

Germ cell tumors are neoplasms arising from pluripotent germ cells. In humans, these tumors occur in infants, children and young adults. The tumors display a wide range of histologic differentiation states which exhibit different clinical behaviors. Information about the molecular basis of germ cell tumors, and representative animal models of these neoplasms, are lacking. Germline development in zebrafish and humans is broadly conserved, making the fish a useful model to probe the connections between germ cell development and tumorigenesis. Here, we provide an overview of germline development and a brief review of germ cell tumor biology in humans and zebrafish. We also outline some methods for studying the zebrafish germline.

Human testicular (non)seminomatous germ cell tumours: the clinical implications of recent pathobiological insights

Human germ cell tumours (GCTs) comprise several types of neoplasias with different pathogeneses and clinical behaviours. A classification into five subtypes has been proposed. Here, the so-called type II testicular GCTs (TGCTs), ie the seminomas and non-seminomas, will be reviewed with emphasis on pathogenesis and clinical implications. Various risk factors have been identified that define subpopulations of men who are amenable to early diagnosis. TGCTs are omnipotent, able to generate all differentiation lineages, both embryonic and extra-embryonic, as well as the germ cell lineage itself. The precursor lesion, composed of primordial germ cells/gonocytes, is referred to as carcinoma in situ of the testis (CIS) and gonadoblastoma of the dysgenetic gonad. These pre-malignant cells retain embryonic characteristics, which probably explains the unique responsiveness of the derived tumours to DNA-damaging agents. Development of CIS and gonadoblastoma is crucially dependent on the micro-environment created by Sertoli cells in the testis, and granulosa cells in the dysgenetic gonad. OCT3/4 has high sensitivity and specificity for CIS/gonadoblastoma, seminoma, and embryonal carcinoma, and is useful for the detection of CIS cells in semen, thus a promising tool for non-invasive screening. Overdiagnosis of CIS due to germ cell maturation delay can be avoided using immunohistochemical detection of stem cell factor (SCF). Immunohistochemistry is helpful in making the distinction between seminoma and embryonal carcinoma, especially SOX17 and SOX2. The different non-seminomatous histological elements can be recognized using various markers, such as AFP and hCG, while others need confirmation. The value of micro-satellite instability as well as BRAF mutations in predicting treatment resistance needs validation in prospective trials. The availability of representative cell lines, both for seminoma and for embryonal carcinoma, allows mechanistic studies into the initiation and progression of this disease.

The pluripotency transcription factor Krüppel-like factor 4 is strongly expressed in intratubular germ cell neoplasia unclassified and seminoma

Germ cell tumors of the testis are the most frequent tumors in men between 20 and 40 years. Their most common subtype is the seminoma, which arises like the embryonal carcinoma from an intratubular germ cell neoplasia unclassified (IGCNU), i.e. fetal germ cells that escaped from the control of the developing testicular stem cell niche, eventually leading to a fully developed seminoma (or embryonal carcinoma). The molecular causes for the development of an IGCNU are still unknown. However, IGCNU cells share the expression of several factors with primordial germ cells and gonocytes and, interestingly, also with pluripotent embryonic stem (ES) cells and induced pluripotent stem (iPS) cells. One factor playing important roles in both iPS and ES cells is the transcription factor Krüppel-like factor 4 (KLF4). This study examined KLF4 expression data from 179 human testicular samples including normal controls and seminoma, deposited in Gene Expression Omnibus repository for microarray data at the National Centre for Biotechnology Information. Immunohistochemistry was used to detect KLF4 protein expression in IGCNU (n = 6), seminoma (n = 14) and fetal human testes (n = 14). Microarray data from three independent sources suggest higher mRNA expression in seminoma than in normal testis. Normal spermatogonia, which are the stem cells of spermatogenesis, controlled by their stem cell niche, do not express KLF4. In contrast, IGCNU and seminoma cells strongly express KLF4. In conclusion, this finding suggests that KLF4 may be an important factor for the maintenance of the developmental and the tumorigenic potential of IGCNU as well as for the malignancy of seminoma.

National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Use of Tumor Markers in Testicular, Prostate, Colorectal, Breast, and Ovarian Cancers

Background: Updated National Academy of Clinical Biochemistry (NACB) Laboratory Medicine Practice Guidelines for the use of tumor markers in the clinic have been developed.

Methods: Published reports relevant to use of tumor markers for 5 cancer sites—testicular, prostate, colorectal, breast, and ovarian—were critically reviewed.

Results: For testicular cancer, α-fetoprotein, human chorionic gonadotropin, and lactate dehydrogenase are recommended for diagnosis/case finding, staging, prognosis determination, recurrence detection, and therapy monitoring. α-Fetoprotein is also recommended for differential diagnosis of nonseminomatous and seminomatous germ cell tumors. Prostate-specific antigen (PSA) is not recommended for prostate cancer screening, but may be used for detecting disease recurrence and monitoring therapy. Free PSA measurement data are useful for distinguishing malignant from benign prostatic disease when total PSA is &lt;10 μg/L. In colorectal cancer, carcinoembryonic antigen is recommended (with some caveats) for prognosis determination, postoperative surveillance, and therapy monitoring in advanced disease. Fecal occult blood testing may be used for screening asymptomatic adults 50 years or older. For breast cancer, estrogen and progesterone receptors are mandatory for predicting response to hormone therapy, human epidermal growth factor receptor-2 measurement is mandatory for predicting response to trastuzumab, and urokinase plasminogen activator/plasminogen activator inhibitor 1 may be used for determining prognosis in lymph node–negative patients. CA15-3/BR27–29 or carcinoembryonic antigen may be used for therapy monitoring in advanced disease. CA125 is recommended (with transvaginal ultrasound) for early detection of ovarian cancer in women at high risk for this disease. CA125 is also recommended for differential diagnosis of suspicious pelvic masses in postmenopausal women, as well as for detection of recurrence, monitoring of therapy, and determination of prognosis in women with ovarian cancer.

Conclusions: Implementation of these recommendations should encourage optimal use of tumor markers.

Stem cell factor as a novel diagnostic marker for early malignant germ cells

Carcinoma in situ (CIS) of the testis is the pre-invasive stage of type II testicular germ cell tumours (TGCTs) of adolescents and adults. These tumours are the most frequently diagnosed cancer in Caucasian adolescents and young adults. In dysgenetic gonads, the precursor of type II GCTs can be either CIS or a lesion known as gonadoblastoma (GB). CIS/GB originates from a primordial germ cell (PGC)/gonocyte, ie an embryonic cell. CIS can be cured by local low-dose irradiation, with limited side effects on hormonal function. Therefore, strategies for early diagnosis of CIS are essential. Various markers are informative to diagnose CIS in adult testis by immunohistochemistry, including c-KIT, PLAP, AP-2gamma, NANOG, and POU5F1 (OCT3/4). OCT3/4 is the most informative and consistent in presence and expression level, resulting in intense nuclear staining. In the case of maturational delay of germ cells, frequently present in gonads of individuals at risk for type II (T)GCTs, use of these markers can result in overdiagnosis of malignant germ cells. This demonstrates the need for a more specific diagnostic marker to distinguish malignant germ cells from germ cells showing maturation delay. Here we report the novel finding that immunohistochemical detection of stem cell factor (SCF), the c-KIT ligand, is informative in this context. This was demonstrated in over 400 cases of normal (fetal, neonatal, infantile, and adult) and pathological gonads, as well as TGCT-derived cell lines, specifically in cases of CIS and GB. Both membrane-bound and soluble SCF were expressed, suggestive of an autocrine loop. SCF immunohistochemistry can be a valuable diagnostic tool, in addition to OCT3/4, to screen for precursor lesions of TGCTs, especially in patients with germ cell maturation delay.

New insights into type II germ cell tumor pathogenesis based on studies of patients with various forms of disorders of sex development (DSD)

Disorders of sex development (DSD), previously known as intersex, refer to congenital conditions in which development of chromosomal, gonadal, or anatomical sex is atypical. Patients with specific variants of this disorder have an elevated risk for the development of so-called type II germ cell cancers, i.e., the seminomatous and nonseminatous tumors, referred to as germ cell tumors (GCTs). Specifically DSD patients with gonadal dysgenesis or hypovirilization are at risk. A prerequisite for type II GCT formation is the presence of a specific part of the Y chromosome (referred to as the GBY region), with the TSPY gene being the most likely candidate. Also the octamer binding transcription factor OCT3/4 is consistently expressed in all type II GCTs with pluripotent potential, as well as in the precursor lesions carcinoma in situ (CIS) in case of a testis and gonadoblastoma (GB) in the DSD gonad. The actual risk for malignant transformation in individual DSD patients is hard to predict, because of confusing terminology referring to the different forms of DSD, and unclear criteria for identification of the presence of malignant germ cells, especially in young patients. This is specifically due to the phenomenon of delay of germ cell maturation, which might result in over diagnosis. This review will give novel insight into the pathogenesis of the type II GCTs through the study of patients with various forms of DSD for which the underlying molecular defect is known. To allow optimal understanding of the pathogenesis of this type of cancers, first normal gonadal development, especially regarding the germ cell lineage, will be discussed, after which type II GCTs will be introduced. Subsequently, the relationship between type II GCTs and DSD will be described, resulting in a number of new insights into the development of the precursor lesions of these tumors.

Testicular cancer and genetics knowledge among familial testicular cancer family members

PURPOSE

It was our aim to determine baseline levels of testicular cancer and genetics knowledge among members of families with Familial Testicular Cancer (FTC).

METHODS

This is a sub-study of an ongoing National Cancer Institute (NCI) multidisciplinary, etiologically-focused, cross-sectional study of FTC. We evaluated 258 male and female participants including testicular cancer (TC) survivors, blood relatives and spouses to assess factors associated with a Genetic Knowledge Scale (GKS) and Testicular Cancer Knowledge Scale (TCKS).

RESULTS

Knowledge levels were generally low, with genetic knowledge lower than TC knowledge (p < 0.01). Men with a personal TC history scored highest on TC knowledge, while gender, age and education differentially influenced knowledge levels, particularly among unaffected relatives.

CONCLUSIONS

Prior to identifying FTC susceptibility genes, we recommend tailoring FTC genetic education to the different informational needs of TC survivors, their spouses and relatives, in preparation for the day when clinical susceptibility testing may be available.

Evidence of testicular dysgenesis syndrome in the dog

Human male reproductive disorders comprising testicular dysgenesis syndrome (TDS) have become more prevalent during the last 50 years. These disorders include cryptorchidism, hypospadias, decreased semen quality, and the development of seminomas. Based on experimental evidence, it has been suggested that environmental pollutants with oestrogen-like or anti-androgenic activities play a role in the pathogenesis of TDS. In humans, histological lesions associated with TDS have been well characterized; this includes seminomas as well as their precursors, carcinoma in situ (CIS) lesions. CIS are seminiferous tubules lined by gonocytes and are a sign of testicular maldevelopment. Such CIS have recently been described in canine species, and an increased frequency of testicular tumours in dogs has also been reported. In this study, we investigated the presence of TDS lesions in canine testes submitted to routine histological examination. Histological features considered typical of human TDS were observed in 8/38 dogs examined; as in humans, individual dogs presented with various TDS features with a range of severity. In all eight dogs, CIS and at least one of the histological feature of TDS was observed in combination with seminoma. These findings suggest that as in humans, TDS may predispose canines to develop testicular cancer. A larger study is needed to better evaluate the actual incidence of TDS in canines, its clinical consequences, and the possible underlying pathogenic factors.

Application of stem cell markers in search for neoplastic germ cells in dysgenetic gonads, extragonadal tumours, and in semen of infertile men

Germ cell tumours (GCTs) are a complex entity. Current areas of attention include early detection and avoidance of unnecessary over-treatment. Novel findings regarding diagnosis of GCTs located in various anatomical sites are described, particularly testicular GCTs and their common progenitor, carcinoma in situ (CIS). Recognition of CIS enables intervention before tumour development, but nevertheless, testicular GCTs are sporadically diagnosed at the pre-invasive stage where minimal treatment is necessary. As presence of CIS is asymptomatic, a simple screening method is needed when CIS is suspected (i.e. in males investigated for infertility). To develop approaches for early detection CIS gene expression studies have been performed showing many similarities with embryonic stem cells with confirmation of established markers (i.e. PLAP, OCT-3/4, KIT) and identification of novel markers (i.e. AP-2 gamma, NANOG). We have reported a very promising new approach of AP-2 gamma (or OCT3/4) based immunocytological semen analysis (specificity 93.6%, sensitivity 54.5%). Comparative studies of gonadal/extragonadal GCTs have revealed resemblance pointing towards similar, but not identical, origins. Moreover, infertility and testicular cancer are connected in the 'Testicular Dysgenesis Syndrome' and 25% of contralateral testes from testicular GCT patients harbour dysgenetic features, including impaired spermatogenesis. Thus, recent data have provided potential diagnostic tools including CIS detection in semen, microarray-based tumour classification, additional serological GCT markers, and novel stem cell markers for immunohistochemical diagnosis of gonadal and extragonadal GCTs. Many CIS candidate genes are yet uninvestigated, and information from these could increase knowledge about CIS tumour initiation/progression and be used for optimisation of a non-invasive detection method.

Heterogeneous Distribution of ITGCNU in an Adult Testis: Consequences for Biopsy-Based Diagnosis

Carcinoma in situ (CIS) of the testis, also referred to as intratubular germ cell neoplasia unclassified (ITGCNU), is currently accepted as the common precursor for all malignant germ cell tumors of adolescents and adults— that is, the seminomatous and nonseminoma cancers. These preinvasive cells have specific cellular characteristics, which can be used for the early diagnosis—routinely done by morphological analysis, sometimes supported by immunohistochemistry—of tissue obtained by an open surgical biopsy. False-negative biopsy results can occur mostly because of the nonrandom distribution of ITGCNU within the testis, misdiagnosis, or suboptimal tissue treatment and analysis. In this article, we demonstrate the potential pitfalls in the diagnosis of ITGCNU. The results support the use of the highly specific and sensitive immunohistochemical marker OCT3/4 for the diagnosis of ITGCNU and provide evidence for the nonrandom distribution of ITGCNU, which is a significant limitation in the diagnosis of this preinvasive lesion.

Malignant germ cell tumours in the elderly: a histopathological review of 50 cases in men aged 60 years or over

Malignant testicular germ cell tumours in the elderly are extremely rare with anecdotal accounts of their aggressive behaviour. Fifty cases of germ cell tumour, diagnosed at the age of 60 years or above, were pathologically reviewed. The oldest patient was 86 years of age, with 78% of cases presenting in men in their 60s. Forty-one (82%) of the tumours were seminomas with only nine cases (18%) of mixed or non-seminomatous germ cell tumour. However, all non-seminomatous types of tumour were represented in the series. The macroscopic tumour size was significantly larger (median=6 cm, range=2-11 cm) than comparable series in younger men. They were also of higher stage with more frequent vascular invasion and rete testis invasion than is typically seen in a younger population. The tumours were less associated with intratubular germ cell neoplasia than in younger men as it was present in only 47% of assessable cases. We conclude that germ cell tumours, in man aged 60 years or above, present at a later stage than in younger men, and although most are seminomas, non-seminomatous tumours may occur with a wide spectrum of morphology.

Association of Intratubular Seminoma and Intratubular Embryonal Carcinoma With Invasive Testicular Germ Cell Tumors

The classification of intratubular germ cell neoplasia of the testis includes an unclassified type (IGCNU), in addition to various other intratubular lesions that show specific forms of differentiation, such as intratubular seminoma and intratubular embryonal carcinoma. Although IGCNU is recognized as a precursor lesion for testicular germ cell tumors, the relationship between differentiated types of intratubular germ cell neoplasia and invasive germ cell tumors of the testis is not well established. The aim of the present study was to examine the association between invasive testicular germ cell tumors and intratubular neoplastic lesions, with particular emphasis on differentiated types of intratubular germ cell neoplasia. The seminiferous tubules adjacent to 42 testicular germ cell tumors were evaluated for the presence of various forms of intratubular germ cell neoplasia. IGCNU was observed in 37 (88%) of 42 cases, whereas intratubular seminoma and intratubular embryonal carcinoma were seen in 19% and 7% of the cases, respectively. Intratubular seminoma was associated primarily with seminomas or mixed germ cell tumors with a seminomatous component, but was also present in a case of a nonseminomatous germ cell tumor. Intratubular embryonal carcinoma was associated exclusively with nonseminomatous germ cell tumors. All cases of intratubular embryonal carcinoma were identified morphologically and exhibited histologic features corresponding to traditional definitions of this lesion. No examples of intratubular embryonal carcinoma as defined by CD30 expression alone in the absence of an intratubular proliferation were observed. The presence of intratubular seminoma in a nonseminomatous germ cell tumor suggests that it is a true preinvasive lesion rather than a manifestation of intratubular spread of an established invasive seminoma. The low incidence of intratubular embryonal carcinoma supports the theory that most nonseminomatous germ cell tumors evolve initially as seminomas, rather than directly from a differentiated intratubular neoplastic lesion.

Non-tumoural parenchyma in Leydig cell tumours: pathogenetic considerations

Little is known about the pathogenesis of Leydig cell tumours (LCTs) of the testis. The observation of several associated dysgenetic features in the non-tumoural parenchyma and in the contralateral testes of men with testicular germ cell neoplasms has served as the basis to propose that there may be a common mechanism for different male reproductive disorders. However, the possible relationship between LCTs and other testicular lesions has not been explored. Here we describe the presence of primary lesions in the non-tumoural parenchyma of testes with LCT, from which we try to establish possible pathogenetic associations. We studied the non-tumoural parenchyma adjacent to 16 LCT specimens. Parameters as Leydig cell hyperplasia (LCHY), qualitative evaluation of the germinal epithelium and spermatogenesis, the presence of Sertoli cell-only tubules (SCOT), and the Sertoli cell nuclear morphology were consistently assessed in all cases. SCOT associated with Sertoli cell dysgenetic morphology was the most frequent finding, present in 50% of the cases. Another interesting finding was the presence of LCHY in four cases (25%). Abnormal spermatogenesis was found in 81.25% of the cases, and it consisted of lesions of the adluminal or basal compartments of seminiferous tubules. The occurrence of either dysgenetic Sertoli cells or LCHY adjacent to LCTs could represent primary anomalies, resulting from a common insult also involved in tumourigenesis. The abnormalities in spermatogenesis observed here are likely to represent consequences of either tumour compression or abnormal hormonal production. The significance of these associations merits further investigation regarding a common pathogenesis.

Does histopathologic tumor type or vascular invasion influence spermatogenesis in testicular cancer?

OBJECTIVE

To assess the quality and activity of spermatogenesis in the contralateral healthy testicle at the time of orchiectomy and to assess whether any tumor-related factor such as tumor type or vascular invasion is a risk factor for impaired spermatogenesis.

DESIGN

Retrospective cohort study.

SETTING

University hospital.

PATIENT(S)

Seventy-six patients undergoing orchiectomy for seminoma or nonseminomatous germ cell tumor (NSGCT).

INTERVENTION(S)

Open biopsy of contralateral healthy testicle at the time of orchiectomy.

MAIN OUTCOME MEASURE(S)

Quality of spermatogenesis using median and highest Johnsen score in correlation with histopathologic tumor type, vascular invasion, and serum tumor markers and hormone levels.

RESULT(S)

Contralateral spermatogenesis is reduced in seminomas and in NSGCTs, with median Johnsen scores of 8.9 and 8.6, respectively. Similar results were seen in tumors with vascular invasion (median Johnsen score 8.8 [range 8.2-9.5]) and without vascular invasion (median Johnsen score 8.8 [range 8.1-9.2]). Areas with good-quality spermatogenesis were found in 88.9% of seminoma and 92.5% of NSGCT biopsies.

CONCLUSION(S)

Testicular cancer is associated with impaired spermatogenesis, but neither the histopathologic tumor type nor the presence of vascular invasion correlated with significantly reduced spermatogenesis.

Primary testicular lesions are associated with testicular germ cell tumors of adult men

The present study aims to establish the nature and frequency of testicular lesions in the parenchyma adjacent to testicular germ cell tumors (TGCT) to improve understanding of the factors involved in the development of testicular cancer. Fifty-three cases of TGCT that were fixed in both neutral-buffered formalin and Bouin solution, allowing for the nuclear characterization of Sertoli cells (SCs), were included in this study. In each case, at least 3 sections of different areas of preserved parenchyma surrounding the TGCT were studied. We found Leydig cell hyperplasia, microlithiasis, angiopathy, adenomatous hyperplasia of the rete testis, SC nodules, SC dysgenesis and involution, SC-only tubules, tubular atrophy, adluminal compartment lesions, hypospermatogenesis associated with spermatocyte sloughing, spermatogonial maturation arrest, and hypertrophic and multinucleated spermatogonia. These lesions were found in regions both adjacent and far away from the tumoral mass, and abnormal seminiferous tubules were found intermingled with those showing complete spermatogenesis, suggesting that these lesions are primary and existed before the development of the tumor. Our study suggests that SCs might play a more important role in the development of testicular tumors than previously thought. Our data supports the hypothesis that there is an abnormal differentiation of SCs, caused either by genetic anomalies or by environmental agents during fetal life. This abnormal SC differentiation may cause not only primary spermatogenesis failure and spermatogenesis arrest at different levels, but may also contribute to the poor differentiation of gonocytes into spermatogonia. The abnormal gonocyte differentiation might favor the development of dysplastic germ cells that may later transform into intratubular germ cell neoplasia, unclassified type.

Towards a non-invasive method for early detection of testicular neoplasia in semen samples by identification of fetal germ cell-specific markers

BACKGROUND

Testicular germ cell tumours (TGCTs) originate from a common precursor, carcinoma in situ (CIS). Diagnosis at the CIS stage is desirable as it minimizes the necessary treatment. A detailed clinical evaluation of an approach to detect CIS cells in the ejaculate using primordial germ cell/gonocyte markers is presented.

METHODS

Immunocytological staining for AP-2gamma [and in some cases, OCT-3/4, NANOG or placental alkaline phosphatase (PLAP)] was performed in semen samples from 294 infertile patients and 209 patients with TGCTs or other diseases.

RESULTS

Presence of AP-2gamma-stained cells was detected in 50% of participants with CIS and in 33.9% of TGCT patients before treatment (non-seminomas: 56.6%, seminomas: 17.4%). OCT-3/4 results were similar to those of AP-2gamma, whereas NANOG and PLAP stainings were unsuitable. Sensitivity was 54.5% for participants harbouring pre-invasive CIS but reduced in participants with overt TGCTs, perhaps because of obstruction. Assay specificity was 93.6%, positive predictive value (PPV) 83.3% and negative predictive value (NPV) 60.3%.

CONCLUSIONS

Immunocytological semen analysis based on expression of fetal germ cell markers in exfoliated cells has auxiliary diagnostic value, as it detects some patients with CIS/incipient tumour, but a negative result does not exclude TGCT. Further effort is needed to improve this assay, for example, by employing a more sensitive biochemical method of detection.

Germ cell lineage differentiation in non-seminomatous germ cell tumours

Human germ cell tumours (GCTs) have long fascinated investigators for a number of reasons. Being pluripotential tumours, they can differentiate into both extra-embryonic and embryonic (somatic) tissues. However, it has never been shown convincingly that, in humans, these tumours are truly totipotent and can also give rise to the germ lineage, the third major differentiation lineage occurring early during embryonic life. Using a number of newly available, distinct, immunohistochemical markers, such as OCT3/4, VASA and TSPY, the occurrence of germ cells was investigated in a number of germ cell tumours. Development of germ cells was identified in three independent non-seminomas, including two pure yolk sac tumours and one mixed tumour composed of yolk sac tumour and immature teratoma. Our finding indicates a previously unknown totipotent potential of human GCTs and raises the question of whether, under certain culture conditions, primordial germ cells could be derived from human GCT cell lines.

Microinvasive germ cell tumor of the testis

Microinvasive germ cell tumor (MGCT) consists of a limited number of malignant germ cells in the intertubular tissue of the testis. The cells have large nuclei, prominent nucleoli, abundant clear cytoplasm, and distinct cellular borders in hematoxylin and eosin staining. MGCT can be the first stage of malignancy in the development of testicular germ cell tumor (TGCT). Biopsies from men with maldescended testes have been reported to contain intratubular germ cell neoplasia, unclassified (IGCN) and MGCT in 1.8% of the examined cases (95% CI 0.5-4.6%). MGCT has also been found in testes of subfertile men and in the contralateral testis of patients with TGCT. MGCT is a frequent finding (19%) in the testicular tissue adjacent to an overt TGCT. Men with a high risk of TGCT may gain from screening for precursor lesions of TGCT with ultrasonography of the testes followed by a testicular biopsy if suspicious abnormalities are found: Treatment is high-voltage radiotherapy for intratubular germ cell neoplasia (IGCN), and orchidectomy for MGCT and germ cell tumor in situ, either intratubular seminoma or intratubular embryonal carcinoma. After local treatment, patients with precursor lesions can be followed with a surveillance program. The mRNA levels of invasion-related genes were evaluated based on a DNA microarray data set, and we found two gene abnormalities most relevant for the invasion of malignant germ cells: matrix metalloproteinase 9 (MMP9) and plasminogen activator, urokinase (PLAU) genes were up-regulated in a study comparing tissue samples of TGCT and IGCN.

Testicular germ-cell tumours in a broader perspective

The germ-cell tumours are a fascinating group of neoplasms because of their unusual biology and the spectacular therapeutic results that have been obtained in these tumours. Traditionally, this group of neoplasms is presented in an organ-oriented approach. However, recent clinical and experimental data convincingly demonstrate that these neoplasms are one disease with separate entities that can manifest themselves in different anatomical sites. We propose five entities, in which the developmental potential is determined by the maturation stage and imprinting status of the originating germ cell. Recent progress begins to explain the apparent unpredictable development of germ-cell tumours and offers a basis for understanding their exquisite sensitivity to therapy.

Microinvasive germ cell tumour (MGCT) adjacent to testicular germ cell tumours

AIMS

To examine the occurrence and prognostic significance of intratubular germ cell neoplasia (IGCN) and microinvasive germ cell tumour (MGCT) in tissue adjacent to testicular germ cell tumours (TGCT) in adults.

METHODS AND RESULTS

The study was based on two Danish studies of adult patients with stage I TGCT and included 255 patients. Of 106 patients with seminoma, 75 [71%, 95% confidence interval (CI) 61, 79] had IGCN without MGCT and nine (8%, CI 4, 15) had both IGCN and MGCT. Of 149 patients with non-seminoma, 62 (42%, CI 34, 50) had IGCN without MGCT, and 32 (22%, CI 15, 29) had both IGCN and MGCT. Non-seminomas with a seminoma component were more often associated with MGCT (23 of 54 testes, 43%, CI 29, 57) than were non-seminomas without this component (nine of 95 testes, 10%, CI 4, 17) (P < 0.000 05, Fisher's exact test). Relapse-free survival was not influenced by the concomitant presence of the two precursor stages in the testes (P = 0.36, and P = 0.19, log rank test, respectively).

CONCLUSIONS

MGCT was a relatively frequent finding in testes adjacent to a macroscopic TGCT. However, neither IGCN nor MGCT predicted relapse for patients with stage I TGCT.

From carcinoma in situ to testicular germ cell tumour

The mechanisms of invasive tumour development from pre-invasive CIS are unknown. We examined changes in functional parameters of the tubular wall according to the increase in CIS cells and tubular size. Immunohistochemistry was performed on 37 testicular specimens from 25 patients with carcinoma in situ and/or malignant germ cell tumour for the detection of actin/myosin in myocytes, and laminin/integrin alpha 6 in the basement membrane of seminiferous tubules. Tumour cells were detected by PlAP, Sertoli cells by inhibin alpha and vimentin and by cytokeratin 18/connexin 26 immunoreactivity, which is selectively expressed together with CIS. Areas showing clusters of tumour cells surrounded by a fibrous sheet could be identified as enlarged tubules because of focal Sertoli cell-specific co-expression of inhibin alpha, vimentin, cytokeratin 18, and connexin 26 immunoreaction. These clusters exhibited an intact basement membrane shown by a persistent laminin/integrin alpha 6 immunoreactivity, but myocytes had lost their contractility indicated by the loss of myosin/actin immunoreactivity. They often showed septa originating from the fibrous sheet containing numerous capillaries. Focal areas of syncytiotrophoblastic cells within classical seminoma also expressing inhibin alpha, cytokeratin 18, and connexin 26 could be differentiated from single Sertoli cells within tumor cell clusters by typical hCG but absence of vimentin immunoreactivity. In contrast to the current concept of CIS cells passing the tubular wall, these data provide evidence for an additional theory, i.e. that the switch from pre-invasive CIS to invasive tumour takes place in situ by tubular enlargement due to tumour cell proliferation followed by Sertoli cell degeneration and conversion of the tubular wall into connective tissue.

Current views on the pathogenesis of testicular germ cell tumours and perspectives for future research: highlights of the 5th Copenhagen Workshop on Carcinoma in situ and Cancer of the Testis

This review article highlights the most important contributions presented at the 5th Copenhagen Workshop on Carcinoma in situ and Cancer of the Testis, which was held in Denmark, August 29-31, 2002. The major themes that emerged at the meeting are critically discussed and perspectives for future research in this field are presented.