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.

Diagnostic value of OCT3/4 for pre-invasive and invasive testicular germ cell tumours

Human testicular germ cell tumours of adolescents and adults (TGCTs), the seminomatous and non-seminomatous germ cell tumours, show morphological and biological similarities to normal embryonic development, presumably determined by their supposed cell of origin, the primordial germ cell/gonocyte. Based on this knowledge, OCT3/4, also known as POU5F1, was recently defined as a diagnostic marker for these tumour types. In the adult testis, positive immunohistochemistry for OCT3/4 is an absolute indicator for the presence of the TGCT precursor carcinoma in situ/intratubular germ cell neoplasia undifferentiated (CIS/ITGCNU), seminoma, and/or embryonal carcinoma. Several studies have confirmed this observation, using the same polyclonal antibody. The present study demonstrates the usefulness of OCT3/4 immunohistochemistry in a diagnostic setting of a consecutively collected series of more than 200 testicular tumours and over 80 testicular biopsies. Moreover, it is shown that a monoclonal antibody directed against OCT3/4 is as informative as the polyclonal antibody, both in immunohistochemistry and in western blot analysis. The antibodies are robust and applicable with different methods of pretreatment and storage of tissue. This allows routine application of this diagnostic marker.

[The epidemiology of tumors of the testes in the Netherlands: accurate rendering by the Registry of Histopathology and Cytopathology (PALGA)]

OBJECTIVE

To investigate recent trends in the incidence of testicular cancer and to describe epidemiological characteristics of various subtypes of testicular cancer.

DESIGN

Descriptive.

METHOD

Using the nationwide registry of pathology reports (PALGA), the incidence of all newly-diagnosed cases of testicular cancer between the years 1991 and 2002 was analyzed according to age and subtype. To test the accuracy of the PALGA figures, a comparison was made with incidence figures (1991-1998) produced by the Netherlands Cancer Registry.

RESULTS

5856 cases of testicular cancer were diagnosed. The age-adjusted incidence increased from 4.8 to 6.6 per 100,000. The incidence of non-seminoma increased to a larger extent than that of seminoma. The incidence of malignant lymphoma of testicular origin did not increase, but it remained the most frequent testicular tumour beyond the age of 65. Non-seminoma was the most common tumour below the age of 30, while seminoma was the most commonly found tumour between the ages of 30 and 65. When PALGA began recording statistics, the incidence figures showed a difference of up to 10% with the figures produced by the cancer registry, but this has decreased to 1-2% in more recent years.

CONCLUSION

The incidence of testicular cancer increased from the 1990s up to 2002. The incidence figures of histopathologically confirmed cases of cancer in the PALGA registry were timely and accurate.

New insights into the pathology and molecular biology of human germ cell tumors

The group of human germ cell tumors (GCTs) is heterogeneous, and comprises neoplasms found at different anatomical locations. They are of interest not only for aspects of their tumor biology, but also from the point of view of developmental biology. GCTs show significant similarities to early germ cell development, most likely related to their cell of origin. Comparative analysis of the tumors and representative normal counterparts can therefore help to define events which are related to the pathogenesis of this cancer. Within the testis, three separate GCT entities have been identified, characterized by differing patho-biological, molecular/cytogenetic, and clinical observations, which will be described in more detail in this review. This article will highlight the most important contributions to the field in the last years. This includes the diagnostic value of OCT3/4, a transcription factor and marker for pluripotency. Furthermore, the invasive GCTs of young adults consistently show a gain of 12p-sequences, of which the exact role, including the gene(s) involved, remains to be elucidated, although interesting candidates have been identified. Finally, treatment sensitivity/resistance of GCTs most likely reflect the intrinsic characteristics of the cells of origin and their derivatives. The pluripotency of GCTs, in particular the possible loss of the embryonic characteristics and acquisition of somatic differentiation, could be a crucial phenomenon in this process.

Raman Spectroscopic Analysis Identifies Testicular Microlithiasis as Intratubular Hydroxyapatite

PURPOSE

As diagnosed by ultrasonography, testicular microlithiasis is associated with various benign and malignant conditions. The molecular constitution of these microliths is largely unknown. Raman spectroscopy provides detailed in situ information about the molecular composition of tissues and to our knowledge it has not been applied to gonadal microliths. We analyzed the molecular composition of gonadal microlithiasis and its surrounding region using Raman spectroscopy in malignant and benign conditions.

MATERIALS AND METHODS

Multiple microliths from 6 independent samples diagnosed with gonadal microlithiasis by ultrasound and histologically confirmed were investigated by Raman spectroscopy. The samples included 4 testicular parenchyma samples adjacent to a germ cell tumor (4 seminomas), a gonadoblastoma of a dysgenetic gonad and testicular biopsy of a subfertile male without malignancy.

RESULTS

Raman spectroscopic mapping demonstrated that testicular microliths were located within the seminiferous tubule. Glycogen surrounded all microliths in the samples associated with germ cell neoplasm but not in the benign case. The molecular composition of the 26 microliths in all 6 conditions was pure hydroxyapatite.

CONCLUSIONS

Microliths in the testis are located in the seminiferous tubules and composed of hydroxyapatite. In cases of germ cell neoplasm they co-localize with glycogen deposits.

Bilateral Testicular Microlithiasis Predicts the Presence of the Precursor of Testicular Germ Cell Tumors in Subfertile Men

PURPOSE

A high prevalence of testicular microlithiasis has been described in adolescent and adult clinical cases of invasive testicular germ cell tumor (TGCT), that is seminomas and nonseminomas. However, to our knowledge it remains to be established whether testicular microlithiasis also indicates the presence of the pre-invasive lesion of this cancer, known as carcinoma in situ (CIS). We determined the predictive value of unilateral and bilateral testicular microlithiasis for CIS in subfertile men, a known risk population for TGCTs (approximately 1%).

MATERIALS AND METHODS

In a retrospective cross-sectional study the association between testicular microlithiasis and CIS was studied in a group of 263 men referred for subfertility. Testicular microlithiasis and CIS were diagnosed in all men by scrotal ultrasound and in testicular histology specimens as part of the routine evaluation of all patients.

RESULTS

Of the 263 subfertile men 53 (20%) had testicular microlithiasis. No CIS or TGCT was identified in the 23 men with unilateral testicular microlithiasis. In contrast, 6 of the 30 men (20%) with bilateral testicular microlithiasis were diagnosed with CIS. Therefore, the prevalence of CIS in subfertile men with bilateral testicular microlithiasis is significantly higher than in patients without testicular microlithiasis (1 of 210, 0.5%) and with unilateral testicular microlithiasis (0 of 23, 0%) (p <0.0001).

CONCLUSIONS

Bilateral testicular microlithiasis is indicative for CIS in subfertile men. Since these men are at particular risk for invasive TGCT, an assessment of testicular microlithiasis is a valuable tool for the early diagnosis of this disease.

Stem cell factor receptor (c-KIT) codon 816 mutations predict development of bilateral testicular germ-cell tumors

Testicular germ-cell tumors (TGCTs) of adolescents and adults originate from intratubular germ cell neoplasia (ITGCN), which is composed of the malignant counterparts of embryonal germ cells. ITGCN cells are characterized, among others, by the presence of stem cell factor receptor c-KIT. Once established, ITGCN will always progress to invasiveness. Approximately 2.5-5% of patients with a TGCT will develop bilateral disease and require complete castration, resulting in infertility, a need for lifelong androgen replacement, and psychological stress. To date, the only way to predict a contralateral tumor is surgical biopsy of the contralateral testis to demonstrate ITGCN. We did a retrospective study of 224 unilateral and 61 proven bilateral TGCTs (from 46 patients, in three independently collected series in Europe) for the presence of activating c-KIT codon 816 mutations. A c-KIT codon 816 mutation was found in three unilateral TGCT (1.3%), and in 57 bilateral TGCTs (93%; P < 0.0001). In the two wild-type bilateral tumors for which ITGCN was available, the preinvasive cells contained the mutation. The mutations were somatic in origin and identical in both tumors. We conclude that somatic activating codon 816 c-KIT mutations are associated with development of bilateral TGCT. Detection of c-KIT codon 816 mutations in unilateral TGCT identifies patients at risk for bilateral disease. These patients may undergo tailored treatment to prevent the development of bilateral disease, with retention of testicular hormonal function.

Xeroderma pigmentosum group a protein and chemotherapy resistance in human germ cell tumors

The exceptional sensitivity of germ cell tumors (GCTs) of adolescents and adults to chemotherapy, in particular to cisplatin, has been attributed to low levels of xeroderma pigmentosum group A protein (XPA), a crucial component of the nucleotide excision repair DNA repair pathway. In different types of solid tumors, resistance to cisplatin has been associated with enhanced expression of XPA. To assess the role of XPA levels in clinical sensitivity and resistance of GCTs to chemotherapy, immunohistochemistry was performed on tumor samples of both unselected patients before therapy and patients with fully documented clinical course before and after therapy. In the case of high XPA levels, fluorescent in situ hybridization was applied to assess the possibility of gene amplification. XPA protein levels were investigated by Western blot analysis after repeated exposure to cisplatin in different GCT-derived cell lines. Finally, XPA levels of both sensitive and cisplatin-resistant GCT cell lines were compared with cell lines derived from other neoplasms. We found that the presence of XPA protein as assessed by immunohistochemistry differs among the various histologies of GCTs. It is found more frequently and with a more homogenous staining pattern in histologic subtypes showing a more differentiated phenotype. Overall, no differences in the presence of XPA was observed between samples of tumors refractory or sensitive to chemotherapy. No XPA gene amplification was found. Interestingly, all tumors resected in relapse after chemotherapy in the refractory group stained positive for XPA. However, XPA was not induced by repeated courses of sublethal doses of cisplatin in GCT-derived cell lines in vitro, and no correlation between XPA protein levels and sensitivity to cisplatin in three GCT-derived cell lines was observed. We therefore conclude that XPA does not play a critical role in overall treatment resistance of GCTs.

Testicular carcinoma in situ in patients with extragonadal germ-cell tumours: the clinical role of pretreatment biopsy

BACKGROUND

The aim of this study was to determine the prevalence of testicular carcinoma in situ (CIS) in patients with a malignant extragonadal germ-cell tumour (EGGCT) and the incidence of metachronous invasive testicular cancer (TC) in relation to the pretreatment demonstration of CIS.

PATIENTS AND METHODS

Sixty-eight patients with EGGCT (53 retroperitoneal, 15 mediastinal) had pre-chemotherapy histological assessment of one (13) or both (55) testicle(s). A total of 123 testicles were examined for the presence of CIS.

RESULTS

Testicular CIS was found in 21 patients (31%) (18 retroperitoneal EGGCT, three mediastinal EGGCT). Two patients had bilateral CIS. Five patients, four of them with proven pretreatment CIS, developed a metachronous TC. The 10-year invasive-free TC survival rate for all 68 patients was 88%, but only 65% for those with proven pretreatment CIS. The overall 10-year survival rate for all patients was 82%. CIS was demonstrated in seven of 48 trans-scrotal core biopsies, in 10 of 56 trans-scrotal surgical biopsies and in five of 11 orchiectomy specimens.

CONCLUSIONS

Approximately one-third of patients with EGGCT present with testicular CIS, predominantly those with a retroperitoneal tumour. These patients have a considerable risk of metachronous TC development in spite of chemotherapy. The pretreatment demonstration of testicular CIS in patients with EGGCT gives the possibility of individualised counselling and safe follow-up, and is therefore highly recommended. The data are in agreement with a multi-site development of malignant germ-cell tumours, but do not exclude the possibility that the retroperitoneal EGGCTs in particular represent metastases from a burned-out TC.

Aneuploidy of human testicular germ cell tumors is associated with amplification of centrosomes

Testicular germ cell tumors occur in three age groups. Seminomas and nonseminomas of adults, including mature teratomas, and the precursor carcinoma in situ (CIS) are aneuploid. This also holds true for yolk sac tumors of newborn and infants, while the mature teratomas of this age are diploid. In contrast, spermatocytic seminomas occurring in the elderly contain both diploid and polyploid cells. Aneuploidy has been associated with centrosome aberrations, sometimes related to overexpression of STK15. Aneuploidy of non-neoplastic germ cells has been demonstrated in the context of male infertility, a risk factor for the development of seminoma/nonseminoma. We investigated aneuploidy, centrosome aberrations and the role of STK15 in different types of testicular germ cell tumors as well as in normal and disturbed spermatogenesis. The aneuploid seminomas and nonseminomas tumors (including CIS) showed increased numbers of centrosomes, without STK15 amplification or overexpression. Four out of six infantile teratomas had normal centrosomes, the remaining two and an infantile yolk sac tumor showed a heterogeneous pattern of cells with normal or amplified centrosomes. Spermatocytic seminomas had two, four or eight centrosomes. Germ cells in seminiferous tubules with disturbed spermatogenesis shared both aneuploidy and centrosome abnormalities with seminomas/nonseminomas and showed a more intense STK15 staining than those with normal spermatogenesis and CIS. Therefore, aneuploidy of testicular germ cell tumors is associated with amplified centrosomes probably unrelated to STK15.

POU5F1 (OCT3/4) identifies cells with pluripotent potential in human germ cell tumors

Human germ cell tumors (GCTs) may have variable histology and clinical behavior, depending on factors such as sex of the patient, age at clinical diagnosis, and anatomical site of the tumor. Some types of GCT, i.e., the seminomas/germinomas/dysgerminomas and embryonal carcinomas (the stem cell component of nonseminomas), have pluripotent potential, which is demonstrated by their capacity to differentiate into somatic and/or extraembryonic elements. Although embryonal carcinoma cells are intrinsically pluripotent, seminoma/germinoma/dysgerminoma cells, as well as their precursor carcinoma in situ/gonadoblastoma cells, have the phenotype of early germ cells that can be activated to pluripotency. The other types of GCT (teratomas and yolk sac tumors of infants and newborn, dermoid cyst of the ovary, and spermatocytic seminoma of elderly) are composed of (fully) differentiated tissues and lack the appearance of undifferentiated and pluripotent stem cells. OCT3/4, a transcription factor also known as OTF3 and POU5F1, is involved in regulation of pluripotency during normal development and is detectable in embryonic stem and germ cells. We analyzed the presence of POU5F1 in GCT and other tumor types using immunohistochemistry. The protein was consistently detected in carcinoma in situ/gonadoblastoma, seminomas/germinoma/dysgerminoma, and embryonal carcinoma but not in the various types of differentiated nonseminomas. Multitumor tissue microarray analysis covering >100 different tumor categories and 3600 individual cancers verified that POU5F1 expression is specific for particular subtypes of GCT of adults. No protein was observed in GCT of newborn and infants, spermatocytic seminomas, and the various tumors of nongerm cell origin. In addition, no difference in staining pattern was found in chemosensitive and chemoresistant GCT of adults. These results indicate preservation of the link between POU5F1 and pluripotency, as reported during normal development, after malignant transformation. Therefore, POU5F1 immunohistochemistry is an informative diagnostic tool for pluripotent GCT and offers new insights into the histological heterogeneity of this cancer.

Expression profile of genes from 12p in testicular germ cell tumors of adolescents and adults associated with i(12p) and amplification at 12p11.2-p12.1

Gain of 12p material is invariably associated with testicular germ cell tumors (TGCTs) of adolescents and adults, most usually as an isochromosome 12p. We analyzed TGCTs with i(12p) using a global approach to expression profiling targeting chromosomes (comparative expressed sequence hybridization, CESH). This indicated overexpression of genes from 12p11.2-p12.1 relative to testis tissue and fibroblasts. The nonseminoma subtype showed higher levels of expression than seminomas. Notably, 12p11.2-p12.1 is amplified in about 10% of TGCTs and CESH analysis of such amplicon cases showed high levels of overexpression from this region. Microarray analysis, including cDNA clones representing most UniGene clusters from 12p11.2-p12.1, was applied to DNA and RNA from 5 TGCTs with amplification of 12p11.2-p12.1 and seven TGCTs with gain of the entire short arm of chromosome 12. Expression profiles were consistent with the CESH data and overexpression of EST595078, MRPS35 and LDHB at 12p11.2-p12.1 was detected in most TGCTs. High-level overexpression of BCAT1 was specific to nonseminomas and overexpression of genes such as CMAS, EKI1, KRAS2, SURB7 and various ESTs correlated with their amplification. Genes such as CCND2, GLU3, LRP6 and HPH1 at 12p13 were also overexpressed. The overexpressed sequences identified, particularly those in the region amplified, represent candidate genes for involvement in TGCT development.

Molecular determinants of treatment response in human germ cell tumors

PURPOSE

Germ cell tumors (GCTs) are highly sensitive to cisplatin-based chemotherapy. This feature is unexplained, as is the intrinsic chemotherapy resistance of mature teratomas and the resistant phenotype of a minority of refractory GCTs. Various cellular pathways may influence the efficacy of chemotherapy. Their impact has not been investigated in a comprehensive study of tumor samples from clinically defined subgroups of GCT patients.

EXPERIMENTAL DESIGN

We investigated proteins involved in regulation of apoptosis (p53, BAX, BCL-2, and BCL-X(L)), cell cycle control [p21 and retinoblastoma protein (RB)], and drug export and inactivation [P-glycoprotein, multidrug resistance-associated protein (MRP) 1, MRP2, breast cancer resistance protein, lung resistance protein, metallothionein, and glutathione S-transferase pi] immunohistochemically in samples of unselected GCT patients (n = 20), patients with advanced metastatic disease in continuous remission after first-line chemotherapy (n = 12), and chemotherapy-refractory patients (n = 24). Mature teratoma components (n = 10) within tumor samples from all groups were analyzed separately. The apoptotic index was studied by terminal deoxynucleotidyl transferase-mediated nick end labeling assay.

RESULTS

Invasive GCTs of all groups showed a correlation between wild-type p53 and apoptotic index (r(s) = 0.66; P < 0.001). The levels of the antiapoptotic proteins BCL-2 and BCL-X(L) were generally low. p21 was hardly detectable and did not correlate with p53 (r(s) = 0.29; P = 0.07). No significant differences among the three patient groups were identified regarding any of the investigated parameters (all Ps were >0.08), even though only individual samples from chemotherapy-resistant cases showed a strong staining for MRP2 and GSTpi. In contrast to other components, mature teratomas showed an intense p21 and RB staining and were mostly positive for MRP2, lung resistance protein, and GSTpi.

CONCLUSIONS

Our results indicate a multifactorial basis for the chemosensitivity of GCTs with lack of transporters for cisplatin, of antiapoptotic BCL-2 family members, of p21 induction by p53, and of RB and an intact apoptotic cascade downstream of p53. These findings suggest a preference for apoptosis over cell cycle arrest after up-regulation of p53. None of the examined parameters offers a general explanation for the chemotherapy-resistant phenotype of refractory tumors. The up-regulation of various factors interfering with chemotherapy efficacy and ability for a p21-induced cell cycle arrest may explain the intrinsic chemotherapy resistance of mature teratomas.

Advanced soft-tissue sarcoma: a disease that is potentially curable for a subset of patients treated with chemotherapy

Adult patients with metastatic or locally advanced irresectable soft-tissue sarcoma (ASTS) are generally considered as incurable. Whether some of these patients achieve long-term survival after first-line treatment with chemotherapy is not known. Patients with ASTS still alive 5 years after initial treatment with a doxorubicin-containing regimen, i.e. long-term survivors, were analysed among the 2187 patients included in first-line chemotherapy protocols between 1976 and 1990 in seven trials of the European Organization for Research and Treatment of Cancer Soft Tissue and Bone Sarcoma Group (EORTC STBSG) group. 1888 patients were followed for at least 5 years. The initial clinical characteristics and the outcome of the long-term survivors were investigated. 66 of the 1888 patients were alive at 5 years and the projected 5-year survival was 8% in this series. Age or histological subtypes were similar in the long-term survivors compared with the other patients. The percentages of females (69%), of grade 1 tumours (35%), of patients with an initial performance status (PS) of 0 (63%) were significantly higher in the long-term survivors while liver metastasis (6% versus 21%) were significantly less frequent. Long-term survivors were observed in all subgroups of patients. 31, 31, 31 and 6% of the long-term survivors were in complete response (CR), partial response (PR), stable disease (SD), and progressive disease (PD), respectively, after the first-line regimen. A CR to a doxorubicin-containing regimen was the major parameter correlated to 5-year survival. In multivariate analysis using a logistic model, independent parameters correlated to 5-year survival were PS, female gender, grade I tumours, and the achievement of a CR after first-line treatment, which was retained as the most powerful predictor for 5-year survival. 10 of the 66 patients died after 5 years in this series, including 8 patients in PD or SD after first-line treatment versus 2 patients in PR or CR (P=0.01). 8% of patients with ASTS are alive 5 years after first-line chemotherapy with a doxorubicin-containing regimen. Long-term survivors are observed in all prognostic subgroups of patients, in particular those achieving a CR to first-line chemotherapy.

Tumour banks: well-guarded treasures in the interest of patients

In order for the genomics revolution to change how we diagnose, categorize and treat cancer, scientists and clinicians must have access to tumour samples. There has therefore never been a better time to create banks of tumour tissue. Collecting and storing tumour samples and their associated data, however, creates numerous methodological, ethical, legal and technical problems. How can we leap these hurdles in a responsible manner and still make full use of the wealth of information that can be obtained from them?

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.

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

A comparative morphological analysis of parenchyma adjacent to testicular germ cell tumours (TGCT) was performed in a series of 181 orchidectomy specimens: 86 with seminomas (Se), 72 with nonseminomatous germ cell tumours (NS) and 23 with combined tumours (CT, which have a Se and a NS component). The following morphological features were semiquantitatively scored: spermatogenesis (modified Johnsen score); amount of tubular atrophy; amount of carcinoma in situ (CIS); amount of intertubular tissue. Absence and presence was scored for the following features: lymphocytic infiltrate surrounding and invading CIS; intratubular seminoma (ISe); intratubular nonseminoma (INS); microlithiasis; diffuse and nodular hyperplasia of Leydig cells; angioinvasiveness; testicular angiopathy. Using non-parametric statistics these features were correlated with each other and with tumour type, tumour size and age of the patient. Se-patients presented at significantly higher age than NS-patients (36 vs 29 years, p=0.001). The age of patients with CT (32 years) was in between that of Se- and NS-patients. No correlation was found between patient age and tumour size. Parenchyma adjacent to Se, compared to parenchyma adjacent to NS had the following significant differences: a lower Johnsen score (5.6 vs 7.2, p=0.005); less frequent (85% vs 97% of specimens, p=0.016) and a lesser amount of CIS (26% vs 32% of tubules, p=0.015); more frequent peri- (80% vs 60% of specimens, p=0.001) and intratubular (68% vs 30% of specimens, p=0.001) lymphocytic infiltrates; more extensive tubular atrophy (36% vs 15% of tubules, p=0.001); and a larger area of intertubular tissue (42% vs 34% of parenchyma area, p=0.016). The pooled Se and CT had a significantly higher frequency of ISe than the NS (31% vs 17% of specimens, p=0.036). With one exception INS was only found adjacent to NS or CT, with a frequency of 16%, and 20% of the specimens, respectively. It was significantly associated with angio-invasiveness. In specimens lacking angio-invasion the frequency of INS was 6%. The correlation of INS with tumour size and patient age was studied in a series of 145 NS and CT (95 from the original series supplemented by 50 newer cases). In this series INS was significantly associated with smaller tumours and younger patients. Extensive tubular atrophy was significantly correlated with higher age, the diagnosis of Se, a low Johnsen score, and the presence of angiopathy. The more tubular atrophy, the less CIS (both in incidence and amount). Inversely, a higher Johnsen score is associated with smaller tumours, the diagnosis of NS or CT, a higher incidence and a larger amount of CIS, and little tubular atrophy. Tubules with mature spermatogenesis were found in 42% of the specimens regardless of tumour type. We conclude that ISe and INS are probably frequent intermediate stages between CIS and Se and NS, respectively. The features of parenchyma adjacent to Se are probably due to the host response elicited by the invasive Se, which secondarily also affects CIS. The long time to clinical presentation allows the host to eradicate most of the CIS by the time the tumour is surgically removed. The much less extensive morphological features of a host response in parenchyma adjacent to NS support the contention that NS originates as INS, behind the blood/testis barrier, without exposure of the host to tumour cells with a seminomatous phenotype (CIS- or Se cells). Microlithiasis and testicular angiopathy are frequent, but not specific findings in parenchyma next to TGCT. Their relationship with the development with TGCT is unexplained.

Role of gain of 12p in germ cell tumour development

Within the human testis, three entities of germ cell tumours are distinguished: the teratomas and yolk sac tumors of newborn and infants, the seminomas and nonseminomas of adolescents and young adults, referred to as testicular germ cell tumours (TGCT), and the spermatocytic seminomas. Characteristic chromosomal anomalies have been reported for each group, supporting their distinct pathogenesis. TGCT are the most common cancer in young adult men. The initiating pathogenetic event of these tumours occurs during embryonal development, affecting a primordial germ cell or gonocyte. Despite this intra-uterine initiation, the tumour will only be clinically manifest after puberty, with carcinoma in situ (IS) as the precursor. All invasive TGCT, both seminomas and nonseminomas, as well as CIS cells are aneuploid. The only consistent (structural) chromosomal abnormalities in invasive TGCT are gains of the short arm of chromosome 12, mostly due to isochromosome (i(12p)) formation. This suggests that an increase in copy number of a gene(s) on 12p is associated with the development of a clinically manifest TGCT. Despite the numerous (positional) candidate gene approaches that have been undertaken thus far, identification of a causative gene(s) has been hampered by the fact that most 12p gains involve rather large genomic intervals, containing unmanageable numbers of candidate genes. Several years ago, we initiated a search for 12p candidate genes using TGCT with a restricted 12p-amplification, cytogenetically identified as 12p11.2-p12.1. This approach is mainly based on identification of candidate genes mapped within the shortest region of overlap of amplification (SROA). In this review, data will be presented, which support the model that gain of 12p-sequences is associated with suppression of apoptosis and Sertoli cell-independence of CIS cells. So far, DAD-R is one of the most likely candidate genes involved in this process, possibly via N-glycosylation. Preliminary results on high through-put DNA- and cDNA array analyses of 12p-sequences will be presented.

Pathobiology of testicular germ cell tumors: views and news

Human germ cell tumors (GCTs) are a heterogeneous group of neoplasms. They can occur in different anatomic locations, predominantly in the gonads (both ovary and testis) and in the midline of the body, including the retroperitoneal, mediastinal and hypothalamus/pineal gland regions. This distribution has been related to the migration routefollowed by primordial germ cells from the yolk sac to the genital ridge. The clinical behavior of these tumors depends on the sex of the patient, the age at clinical presentation and the histology of the tumor, Within the testis, three groups of GCTs can be distinguished; (I) yolk sac tumors and teratomas of neonates and infants; (II) seminomas and nonseminomas of adolescents and adults, the so-called testicular germ cell tumors; and (III) spermatocytic seminomas. This review discusses the histology, epidemiology and chromosomal constitution of GCT, in particular of the seminomas and nonseminomas of the adult testis, including their precursor, carcinoma in situ. In addition, the available data on the molecular basis of treatment sensitivity and resistance of GCT are reviewed.

Absence of c-KIT and members of the epidermal growth factor receptor family in refractory germ cell cancer

BACKGROUND

Germ cell tumors (GCTs) in adolescent and young males are very sensitive to cisplatin-based chemotherapy. However, 10-20% of the patients cannot be cured by currently available therapeutic options. Once a tumor does not respond to cisplatin, current therapeutic modalities offer only a chance for short palliation. Recently, new treatment options that interfere with various receptor tyrosine kinases, including c-KIT and members of the epidermal growth factor receptor (EGFR) family, have been used successfully in chemotherapy-resistant tumors overexpressing c-KIT, ERB-B2, or EGFR.

METHODS

We studied the presence of c-KIT and the four members of the EGFR family by immunohistochemistry, as well as by ERB-B2 gene amplification using fluorescent in situ hybridization, in a series of 22 patients with cisplatin-resistant GCTs in search of new treatment targets. The results in these refractory tumors were compared with those of 12 patients with chemosensitive GCTs diagnosed in an advanced metastatic stage.

RESULTS

The data obtained in both groups did not differ in any of the investigated biologic markers. c-KIT was detected in the one case of pure seminoma studied and in the seminomatous components of combined tumors. The presence of EGFR was restricted to trophoblastic giant cells and the syncytiotrophoblastic elements of four nonseminomas including one pure choriocarcinoma and to a secondary non-germ cell malignancy, which had developed most likely from a mature teratoma. ERB-B2 was moderately positive in the secondary non-germ cell malignancy, in one mature teratoma component of a mixed nonseminoma, and together with EGFR in the syncytiotrophoblastic cells of a pure choriocarcinoma. Of all samples investigated, this latter case was the only one showing an amplification of the ERB-B2 gene in the syncytiotrophoblasts. ERB-B3 and ERB-B4 were detected rarely.

CONCLUSION

The majority of refractory GCTs do not qualify for treatment with new biologic agents targeting the receptor tyrosine kinases EGFR, ERB-B2, or c-KIT. The lack of differences between the tumors of refractory and the responsive patients indicates that overexpression of any of these receptor tyrosine kinases does not contribute to a resistant phenotype in GCTs.

Microsatellite instability of germ cell tumors is associated with resistance to systemic treatment

Systemic cisplatin-based chemotherapy cures > or =90% of patients with metastatic germ cell tumors (GCTs). The biological basis of this exquisite chemo-sensitivity and the resistant phenotype encountered in 10-15% of patients with GCT is yet unclear. A defective mismatch repair pathway leading to microsatellite instability (MSI) has been related to resistance to cytotoxic drugs. We investigated 100 unselected GCTs and 11 clinically defined chemotherapy-resistant GCTs for MSI using 8 mono- or dinucleotide markers and the presence of the mismatch repair factors MLH1, MSH2, and MSH6 by immunohistochemistry. The resistant tumors, both chemo-naïve (n = 8) and pretreated (n = 3), showed a significantly higher incidence of MSI compared with the unselected series (45 versus 6% in at least one locus and 36 versus 0% in > or =2 of 8 loci, both P < or = 0.001). In 5 of all 11 unstable tumors, MSI correlated with immunohistochemical findings. This study demonstrates for the first time a positive correlation between MSI and treatment resistance in GCT.

Involvement of the Fas/FasL pathway in the pathogenesis of germ cell tumours of the adult testis

Induction of apoptosis by Fas ligand (FasL) of Fas-containing cells is a known mechanism involved in the eradication of inappropriate cells during normal development. Alterations of the Fas/FasL pathway have been found in various types of cancer, leading to circumvention of attack of the tumour by the immune system. An alternative way to circumvent eradication by induction of apoptosis is through changes in the downstream inhibitors. For example, Fas-associating phosphatase-1 (Fap-1) binds directly to the Fas receptor and results in a block of the downstream signalling. To shed more light on the role of the Fas/FasL pathway in the development of human testicular germ cell tumours of the adult testis, this study investigated the presence of Fas, FasL, Fap-1, HLA class I and II molecules, CD45 (lymphocyte marker), and CD57 [natural killer (NK) cell marker] by immunohistochemistry on frozen sections of 41 cases of seminomas, non-seminomas, and spermatocytic seminomas. Every germ cell tumour was positive for Fap-1 and negative for HLA classes I and II, like their non-malignant cells of origin. The infiltrating lymphocytes, predominantly present in seminomas, showed consistently positive staining for Fas and CD45, but not for Fap-1. No Fas was found on NK cells. All seminomas and non-seminomas (except teratomas), including their precursor stages, carcinoma in situ, intratubular seminoma and intratubular non-seminoma, showed positive staining for FasL, but not for Fas. Teratoma showed no staining for FasL and was positive for Fas. In contrast, both Fas and FasL were detectable on spermatocytic seminoma. These data indicate a different regulation of the Fas/FasL system in seminoma and spermatocytic seminoma, supporting a separate pathogenesis for these germ cell-derived tumours. The presence of Fap-1 in all histological variants of germ cell tumours might be related to the consistently positive staining in cells of the germ lineage. This study indicates that production of FasL by the germ cell tumour cells might be involved in the early development of these types of adult testicular cancer by inducting apoptosis of Fas-positive, Fap-1-negative tumour-infiltrating lymphocytes.

Expression of the PDGF alpha-receptor 1.5 kb transcript, OCT-4, and c-KIT in human normal and malignant tissues. Implications for the early diagnosis of testicular germ cell tumours and for our understanding of regulatory mechanisms

Human testicular germ cell tumours of adolescents and adults (TGCTs), including their precursor lesion carcinoma in situ (CIS), show expression of a 1.5 kb alternative transcript of the platelet-derived growth factor (PDGF) alpha-receptor gene. The so-called P2 promoter involved is located in intron 12 and its activity was found to be mutually exclusive with activity of the classical promoter (P1), which encodes the full-length receptor. The presence of the 1.5 kb transcript could be a putative marker for the early molecular diagnosis of TGCTs. In order to validate the RT-PCR approach, this study shows that not more than 100 transcripts are necessary to obtain positivity in the test used; moreover, samples from TGCTs or CIS-containing tissues can be diluted many-fold before resulting in false-negative findings. This study also shows that within TGCTs, as in TGCT-derived cell lines, expression of the 1.5 kb transcript is differentiation-dependent and positively correlated with expression of the embryonic transcription factor OCT-4/POU5F1. Furthermore, the results indicate that in some non-TGCT cancers and cell lines the 1.5 kb transcript is also expressed, but without concomitant OCT-4/POU5F1 expression. The 1.5 kb transcript is also present in early B cells and derived leukaemias (B-ALL). In spite of similarities in chromosomal location, down-regulation upon differentiation of TGCTs, and PDGF alpha-receptor and c-KIT (the stem cell factor receptor) both being a tyrosine kinase receptor, no correlation was found between activity of the P2 promoter of the PDGF alpha-receptor gene and expression of c-KIT. In conclusion, the 1.5 kb transcript of the PDGF alpha-receptor is expressed in various cells and tissues, including particular blood cells. Although this may hamper the use of this transcript as a marker for malignancies in general, it does not appear to interfere with assays for the early detection of TGCTs.

Role of P53 and MDM2 in treatment response of human germ cell tumors

PURPOSE

Testicular germ cell tumors (TGCTs) of adolescents and adults are very sensitive to systemic treatment. The exquisite chemosensitivity of these cancers has been attributed to a high level of wild-type P53.

MATERIALS AND METHODS

To clarify the role of P53 in treatment sensitivity and resistance of TGCTs, we performed immunohistochemistry and Western blotting analysis on a series of 39 fresh-frozen primary TGCTs before therapy (unselected series). In a series of formalin-fixed paraffin-embedded TGCTs of patients with fully documented clinical course, including treatment-sensitive (n = 17) and -resistant (n = 18) tumors, P53 status was assessed by immunohistochemistry and mutation analysis. In addition, the involvement of MDM2, a P53 antagonist, was investigated by immunohistochemistry, reverse transcriptase polymerase chain reaction, and in situ hybridization.

RESULTS

Immunohistochemistry demonstrated absence of staining for P53 in 36%, 41%, and 17% of the unselected, responding, and nonresponding TGCTs, respectively. Of the positive TGCTs, most tumors, ie, 49%, 41%, and 33%, showed 1% to 10% positive nuclei. This overall low level of P53 was confirmed by Western blotting. Mutation analysis revealed only one silent P53 mutation in one of the responding patients. All embryonal carcinomas were homogeneously positive for MDM2, encoded by the full length mRNA, while a heterogeneous pattern was found for the other histologic components. Amplification of MDM2 was detected in one out of 12 embryonal carcinomas.

CONCLUSION

Although our results are in line with previous findings of the presence of wild-type P53 in TGCTs, they show that a high level of P53 does not relate directly to treatment sensitivity of these tumors, and inactivation of P53 is not a common event in the development of cisplatin resistance.

Coamplification of DAD-R, SOX5, and EKI1 in human testicular seminomas, with specific overexpression of DAD-R, correlates with reduced levels of apoptosis and earlier clinical manifestation

Seminomas and nonseminomas represent the invasive stages of testicular (TGCTs) of adolescents and adults. Although TGCTs are characterized by extra copies of the short arm of chromosome 12, the genetic basis for gain of 12p in the pathogenesis of this cancer is not yet understood. We have demonstrated that gain of 12p is related to invasive growth and that amplification of specific 12p sequences, i.e., 12p11.2-p12.1, correlates with reduced apoptosis in the tumors. Here we show that three known genes map within the newly determined shortest region of overlap of amplification (SROA): DAD-R, SOX5, and EKI1. Whereas EKI1 maps close to the telomeric region of the SROA, DAD-R is the first gene at the centromeric region within the 12p amplicon. Although all three genes are amplified to the same level within the SROA, expression of DAD-R is significantly up-regulated in seminomas with the restricted 12p amplification compared with seminomas without this amplicon. DAD-R is also highly expressed in nonseminomas of various histologies and derived cell lines, both lacking such amplification. This finding is of particular interest because seminomas with the restricted 12p amplification and nonseminomas are manifested clinically in the third decade of life and show a low degree of apoptosis. In contrast, seminomas lacking a restricted 12p amplification, showing significantly lower levels of DAD-R with pronounced apoptosis, manifest clinically in the fourth decade of life. A low level of DAD-R expression is also observed in normal testicular parenchyma and in parenchyma containing the precursor cells of this cancer, i.e., carcinoma in situ. Therefore, elevated DAD-R expression in seminomas and nonseminomas correlates with invasive growth and a reduced level of apoptosis associated with an earlier clinical presentation. These data implicate DAD-R as a candidate gene responsible in part for the pathological effects resulting from gain of 12p sequences in TGCTs. In addition, our results also imply differences in expression regulation of DAD-R between seminomas and nonseminomas.

The role of the EORTC pathologist in clinical trials: achievements and perspectives. European Organisation for Research and Treatment of Cancer

The role of the pathologist in clinical trials (CT) is focused on three activities: pathology review, translational research, and participation in scientific committees. The primary goal of pathology review in CT is the quality control (QC) of the diagnosis and prognostic parameters. Important contributions have been achieved in the context of QC for CT such as new classifications of diseases or identification of new prognostic markers that are now widely used. Telematics implemented in some EORTC groups markedly facilitate the pathology review. The pathologist has a key-role in translational research for the identification of new targets in tissue specimens that may eventually lead to new therapeutics and for the understanding of the mechanisms involved in tumour progression. The gap between individualised prognosis and therapeutical possibilities has been considerably reduced by the development of drugs targeted on specific molecular defects. The paradigm of this is the treatment of stromal tumours by STI-571. For proper selection of patients to be treated, information on the expression of the molecules involved is needed, which is well suited for pathologists. The access to tissue resources from patients included in CT is a major goal to enhance translational research, both for brand institution and CT organisations. Active involvement of pathologists in scientific committees and interactions with the pharmaceutical industry is mandatory for an optimal design of CT protocols. In addition, translational research is a resource-consuming activity that necessitates an adequate financial flow to create a proper infrastructure at least for sponsored trials to the participating pathology departments and committees.

VASA is a specific marker for both normal and malignant human germ cells

VASA is so far the only known gene in mammals whose expression is specific for the germ cell lineage. We investigated the presence of VASA mRNA and protein in a series of germ cell tumors of different histologic subtypes and anatomic location, as well as in nongerm cell tumors such as testicular lymphomas and Leydig cell tumors. We detected VASA mRNA (by quantitative RT-PCR) and protein (by immunohistochemical staining) in normal spermatogenesis, seminoma (both classic and spermatocytic), carcinoma in situ (the precursor of classic seminoma and nonseminoma), dysgerminoma, and gonadoblastoma. VASA immunostaining was relatively weak in seminomas and dysgerminomas compared with spermatocytic seminomas, despite similar mRNA levels, suggesting that VASA is regulated in part by post-transcriptional mechanisms. A higher staining intensity compared with the invasive counterparts was observed in the precursor lesions (ie, carcinoma in situ and gonadoblastoma). No VASA mRNA or protein was detectable in nonseminomatous germ cell tumors (such as embryonal carcinoma, teratoma, and yolk sac tumor) and derived cell lines, or nongerm cell tumors such as lymphoma or Leydig cell tumor. These results provide direct evidence that some germ cell tumors retain germ cell characteristics, whereas other tumors of germ cell origin result from differentiation and loss of germ cell identity. Furthermore, these findings suggest that VASA is likely to serve as a useful and highly specific biomarker for germ cell tumors, particularly classic and spermatocytic seminoma/dysgerminoma, including their precursor stages.

[Sarcoma of the thoracic wall following mastitis radiotherapy 38 years previously]

A 62-year-old woman presented with a feeling of pressure between her shoulder blades. Physical examination and laboratory test showed no abnormalities. Conventional X-ray of the thorax showed, by chance, a condensation of the second rib. CT scan showed a solitary lesion at the same location. Patient's history mentioned post-partum mastitis 38 years earlier, for which she was treated with X-ray therapy of about 4 to 5 Gray in 1 fraction. A partial rib resection was performed prior to diagnosis. The histopathological diagnosis was stage IA chondrosarcoma. It was excised in toto and an uneventful disease course ensued. In the past, X-ray therapy was used for many different benign diseases. Many doctors nowadays are not aware of this. This case illustrates that radiotherapy for benign disease can give rise to post irradiation sarcomas. Long-term follow-up of an irradiated region is essential for early diagnosis and may lead to higher cure rates.

Improved pre-operative mediastinal staging in non-small-cell lung cancer by serial sectioning and immunohistochemical staining of lymph-node biopsies

OBJECTIVE

Mediastinal staging of non-small-cell lung carcinoma (NSCLC) by mediastinoscopy suffers from a low sensitivity, leading to a number of patients with unforeseen N2 disease at thoracotomy. This study was undertaken to assess whether pre-operative staging could be improved by serial sectioning and immunohistochemical staining of mediastinoscopy biopsies.

METHODS

In 183 consecutive patients with NSCLC, a thoracotomy was performed after a thorough mediastinal staging by computed tomography scan and cervical mediastinoscopy. In 158 patients (88%), a mediastinal node dissection was performed, revealing unforeseen N2 disease in 24 cases (15%). The preserved mediastinoscopy biopsies of these patients were retrospectively serially sectioned and stained with MNF 116.

RESULTS

Metastases could be identified in seven cases (30%), reducing unforeseen N2 disease from 15 to 10%. The number of patients who could theoretically benefit from neo-adjuvant therapy would have been increased by at least 10%.

CONCLUSIONS

Pre-operative mediastinal staging can be improved considerably by serial sectioning and immunohistochemical staining of mediastinoscopic biopsy specimens.

A randomised phase II study on neo-adjuvant chemotherapy for 'high-risk' adult soft-tissue sarcoma

The aim of this study was to examine the strategy, feasibility and outcome of neo-adjuvant chemotherapy, with doxorubicin and ifosfamide, in adult patients with 'high-risk' soft-tissue sarcomas. Patients with 'high-risk' soft-tissue sarcomas, defined as tumours > or =8 cm of any grade, or grade II/III tumours <8 cm, or grade II/III locally recurrent tumours, or grade II/III tumours with inadequate surgery performed in the previous 6 weeks and therefore requiring further surgery, were randomised between either surgery alone or three cycles of 3-weekly doxorubicin 50 mg/m(2) intravenous (i.v.) bolus and ifosfamide 5 g/m(2) (24 h infusion) before surgery. The type of surgery had to be planned at randomisation. Tumours were to be amenable to surgery by amputation, compartmental resection, wide or marginal excision. If chemotherapy was given, surgery had to be performed within 21 days after the last chemotherapy. Patients received postoperative radiotherapy in cases of marginal surgery, microscopically incomplete resection and no further possibility for surgery, and in cases of surgery because of local recurrence. 150 patients were entered into the study and 134 were eligible, 67 in each arm. The most frequent side-effects of chemotherapy were alopecia, nausea and vomiting (95%), and leucocytopenia (32%). One patient died of neutropenic fever after the first cycle of chemotherapy. Chemotherapy did not interfere with planned surgery and did not affect postoperative wound healing. Limb-salvage was achieved in 88%, amputation was necessary in 12% (all according to the plan at randomisation). The trial was closed after completion of phase II, since accrual was too slow to justify expanding the study into the scheduled phase III study. At a median follow-up of 7.3 years, the 5 year disease-free survival is estimated at 52% for the no chemotherapy and 56% for the chemotherapy arm (standard error: 7%) (P=0.3548). The 5 year overall survival for both arms is 64 and 65%, respectively (standard error 7%) (P=0.2204). Neo-adjuvant-chemotherapy with doxorubicin and ifosfamide at these doses and with this schedule was feasible and did not compromise subsequent treatment, surgery with or without radiotherapy. Although not powered to draw definitive conclusions on benefit, but with an at least 7 year median follow-up, the results render it less likely that major survival benefits will be achieved with this type of chemotherapy.

Clinical impact of germ cell tumor cells in apheresis products of patients receiving high-dose chemotherapy

PURPOSE

High-dose chemotherapy (HD-Ctx) followed by autologous peripheral-blood stem-cell (PBSC) transplantation is currently investigated in patients with poor prognosis or relapsed metastatic germ cell tumor (GCTs). This study analyzed the presence and the clinical importance of contaminating tumor cells in PBSC preparations used to support HD-Ctx in GCT patients.

PATIENTS AND METHODS

Seven targets for reverse transcription polymerase chain reaction (RT-PCR)-based detection of GCT cells were able to detect seminomatous and different histologic variants of nonseminomatous tumor cells. PBSC preparations from 57 patients were investigated for the presence of contaminating tumor cells using this set of targets, including beta human chorionic gonadotropin (beta-hCG), fibronectin (EDB variant), epidermal growth factor receptor (EGFR), CD44 (v8 to 10 variant), germ cell and placental alkaline phosphatase (AP), human endogenous retrovirus type K (ENV and GAG), and XIST. Samples of PBSC preparations from four healthy donors for allogenic transplantations as well as blood specimens from 10 healthy volunteers served as negative controls.

RESULTS

Fifty patients (43 first-line and seven second-line Ctx) were assessable. Combining all RT-PCR results, 29 PBSC preparations (58%) were positive for tumor-specific amplification products (HERV-K 0, fibronectin 4, XIST 14, beta-hCG 19, AP 19, CD44 24, EGFR 26). Ten (35%) of 29 patients who underwent transplantation with positive PBSC preparations and seven (33%) of 21 patients with negative PBSC preparations have suffered relapse or progression (not significant [ns]). With a median follow-up of 22 months (2 to 66) post-HD-Ctx projected 3-year survival rates are 68% (RT-PCR+) and 58% (RT-PCR-) (ns). None of the 10 control peripheral-blood samples showed positivity for any of the targets studied.

CONCLUSION

GCT cells can be detected in more than 50% of PBSC preparations using a RT-PCR approach with multiple targets. Despite the presence of tumor cells, retransplantation of the PBSC products did not effect long-term outcome. Factors such as responsiveness to chemotherapy and tumor mass seem to overcome the importance of potentially re-infused tumor cells.

Carcinoma in situ in the testis

Carcinoma in situ (CIS) of the testis is a common precursor of germ-cell tumours in adults and adolescents, with the exception of spermatocytic seminoma. This article reviews existing knowledge on the pathobiology, genetic aspects and epidemiology of CIS, discusses current hypotheses concerning pathogenesis and invasive progression of germ-cell neoplasms and provides guidelines for diagnosis and clinical management of CIS.

Overrepresentation of the short arm of chromosome 12 is related to invasive growth of human testicular seminomas and nonseminomas

Overrepresentation of 12p-sequences, mostly due to isochromosome formation, is the only consistent chromosomal alteration found in invasive testicular germ cell tumors of adolescents and young adults (TGCTs), both seminomas and the various histological elements of nonseminomas. The biological role of extra 12p in the pathogenesis of this cancer is unclear, and it is also unknown so far, whether it is an early event, i.e., already present in carcinoma in situ, or related to invasive growth. Using comparative genomic hybridization (CGH) with DOP-PCR amplified DNA isolated from micro-dissected tumor cells, and double fluorescent in situ hybridization (FISH) on frozen tissue sections, we investigated the presence of overrepresentation of 12p sequences in different development stages of four seminomas and seven nonseminomas, in total 17 invasive components, in addition to the carcinoma in situ of each. CGH demonstrated relative gain of 12p-sequences in all invasive components except one, confirmed by FISH in most samples. In contrast, no gain was found in the carcinoma in situ samples by any of the methods. These findings show that overrepresentation of 12p is not an early event in the development of TGCTs, but relates to invasive growth.

Restricted 12p amplification and RAS mutation in human germ cell tumors of the adult testis

Human testicular germ-cell tumors of young adults (TGCTs), both seminomas and nonseminomas, are characterized by 12p overrepresentation, mostly as isochromosomes, of which the biological and clinical significance is still unclear. A limited number of TGCTs has been identified with an additional high-level amplification of a restricted region of 12p including the K-RAS proto-oncogene. Here we show that the incidence of these restricted 12p amplifications is approximately 8% in primary TGCTs. Within a single cell formation of i(12p) and restricted 12p amplification is mutually exclusive. The borders of the amplicons cluster in short regions, and the amplicon was never found in the adjacent carcinoma in situ cells. Seminomas with the restricted 12p amplification virtually lacked apoptosis and the tumor cells showed prolonged in vitro survival like seminoma cells with a mutated RAS gene. However, no differences in proliferation index between these different groups of seminomas were found. Although patients with a seminoma containing a homogeneous restricted 12p amplification presented at a significantly younger age than those lacking it, the presence of a restricted 12p amplification/RAS mutation did not predict the stage of the disease at clinical presentation and the treatment response of primary seminomas. In 55 primary and metastatic tumors from 44 different patients who failed cisplatinum-based chemotherapy, the restricted 12p amplification and RAS mutations had the same incidence as in the consecutive series of responding patients. These data support the model that gain of 12p in TGCTs is related to invasive growth. It allows tumor cells, in particular those showing characteristics of early germ cells (ie, the seminoma cells), to survive outside their specific microenvironment. Overexpression of certain genes on 12p probably inhibits apoptosis in these tumor cells. However, the copy numbers of the restricted amplification of 12p and K-RAS mutations do not predict response to therapy and survival of the patients.

Allelic losses in carcinoma in situ and testicular germ cell tumours of adolescents and adults: evidence suggestive of the linear progression model

Testicular germ cell tumours (TGCTs) may arise through a process of multi-step carcinogenesis, and loss of heterozygosity (LOH) at specific loci is likely to be an important early event, although this has not been studied in detail. In order to explore the pathogenetic relationships among TGCTs, we investigated the genetic changes in testicular tumours that exhibit a disease continuum through the precursor carcinoma in situ (CIS) to either seminoma (SE) and/or non-seminomatous germ cell tumour (NSGCT). Universal amplification has been performed on 87 TGCT specimens and 36 samples of CIS cells microdissected from single paraffin-embedded tumour sections from 40 patients, including multiple specimens of CIS and TGCT cells of varied histology microdissected from 24 individual patients. Seventy-seven microsatellite markers were used to assay these samples for LOH at candidate regions selected from the literature, mapping to 3q, 5q, 9p, 11p, 11q, 12q, 17p and 18q. Construction of deletion maps for each of these regions identified common sites of deletion at 3q27-q28, 5q31, 5q34-q35, 9p22-p21 and 12q22, which correlate with allelic losses we have also observed in the precursor CIS cells. Evidence for allelic loss at 3q27-q28 was observed in all of the embryonal carcinoma samples analysed. We conclude that inactivation of gene(s) within these regions are likely to be early events in the development and progression of TGCTs. These results also provide molecular evidence in support of the hypothesis that SE is an intermediate stage of development within a single neoplastic pathway of progression from CIS precursor cells to NSGCT.

MIB-1 as a proliferative marker in transitional cell carcinoma of the bladder: clinical significance and comparison with other prognostic factors

BACKGROUND

Staging and grading of transitional cell carcinoma of the bladder are generally viewed as indicators of prognosis and form the basis of therapy, but they do not predict outcome accurately. This study was designed to evaluate the value for predicting recurrence, progression, and survival of proliferation fraction in transitional cell carcinoma of the bladder determined by immunostaining of histopathologic specimens with the monoclonal antigen MIB-1.

METHODS

In a prospectively followed group of 301 patients with transitional cell carcinoma of the bladder, formalin fixed tumor specimens were immunostained and the MIB-1 labeling index was determined. Crude survival, progression free survival, and recurrence free survival (for patients with Ta and T1 tumors) were assessed in univariate and multivariate analysis according to stage, grade, mitotic index of the tumor, and patient age. The median value of continuous variables was used as a cutoff point in statistical analysis.

RESULTS

In univariate analysis there was a strong association between all included factors and crude survival, progression free survival, and recurrence free survival with a median follow-up period of 60 months. In multivariate analysis, crude survival and progression free survival were determined by stage (P = 0.0001) and age (P = 0.0001). Recurrence free survival for patients with Ta and T1 tumors was determined by MIB-1 labeling index (P = 0.0317), mitotic index (P = 0.0229), and age (P = 0.0001).

CONCLUSIONS

MIB-1 immunostaining in transitional cell carcinoma of the bladder correlated well with grade, stage, and clinical outcome. In multivariate analysis, proliferation fraction had prognostic value in predicting recurrence free survival for patients with Ta and T1 tumors, whereas stage and age appeared to be predictors of progression free survival.

Comparative genomic hybridization of microdissected samples from different stages in the development of a seminoma and a non-seminoma

Human testicular germ cell tumours (TGCTs) of adolescents and adults, both seminomas and non-seminomas, originate from intratubular germ cell neoplasia (IGCN). Comparative genomic hybridization (CGH) was applied to microdissected samples from different stages of the development of a seminoma and a mixed non-seminoma, including IGCN of both. The different stages of the seminoma development, namely IGCN, intratubular and invasive seminoma, showed a very similar pattern of chromosomal imbalances, including gains of parts of 7, 8, 12,14, and X, and losses of parts of 3, 4, 5, 10, 11, 12q, 16, 18, 22, and Y. A more heterogeneous pattern was found for the non-seminoma. Some aberrations were present only in IGCN, or in IGCN and in all invasive components (gains of parts of 1q, 17, 19p, 20q, and 22, and losses of parts of 4, 5, 9p, 13, and 18q), while others were present in a less consistent pattern. These are the first reported CGH data from different stages in the development of TGCTs. Although only two cases were studied, the results suggest that particular numerical changes of (parts of) chromosomes are involved in the early development and progression of this cancer.

Effect of high-dose ifosfamide in advanced soft tissue sarcomas. A multicentre phase II study of the EORTC Soft Tissue and Bone Sarcoma Group

In this phase II study the effect of high-dose ifosfamide (HDI) given as a 3-day continuous infusion at a dose of 12 g/m2 repeated every 4 weeks with adequate mesna protection and hydration was evaluated in patients with advanced soft tissue sarcomas. A total of 124 patients entered the trial of which 10 were ineligible. HDI was given both as first-line and second-line chemotherapy. Median age was 46 years (19-66 years). Median World Health Organization (WHO) performance status was 1 (0-1). Fifty two per cent of the patients were males. The predominant histology was leiomyosarcoma (33%). A maximum of six cycles was given. At the time of analysis 55 patients have died. The partial response (PR) rate was 16%. The median time to progression was 15 weeks. 8 of the 18 responding patients (44%) had synovial sarcomas, whereas only 5% of the patients having leiomyosarcomas responded. The grade 3 + 4 haematological toxicity encountered was neutrophils in 78% and platelets in 12%. The major grade 3 + 4 non-haematological toxicities encountered were febrile neutropenia in 39%, infection in 20%, and acute renal failure in 4%. In conclusion, it is possible to administer HDI on a multicentre basis, but the toxicity is substantial. HDI given as a continuous infusion at this dose cannot be recommended as the standard treatment of advanced soft tissue sarcomas, even in selected patients.

A molecular model for the development of germ cell cancer

Human germ cell tumors comprise a heterogeneous group of neoplasms. Those of the adult testis, known as TGCTs, originate from carcinoma in situ (CIS), which are initiated during intra-uterine development. We present here a molecular model for the development of TGCTs, including various parameters, such as apoptosis, chromosomal constitution, as well as genomic imprinting. We assume that TGCTs originate from a pluripotent, erased embryonic germ cell, of which aneuploidization is one of the early events. Subsequently, net loss and gain of specific chromosomal regions result in the consistent pattern of chromosomal aberrations that are observed in these tumors, including gain of 12p-sequences. By means of analysis of a relatively small region of the short arm of chromosome 12, we are in the process of identifying the relevant genes. Possibly, this gene(s) suppresses apoptosis outside the specific micro-environment of the seminiferous tubule.

Chromosomal gains and losses in testicular germ cell tumors of adolescents and adults investigated by a modified comparative genomic hybridization approach

Testicular germ cell tumors of adolescents and adults, both seminomas (SE) and nonseminomas (NS), are aneuploid, and classical karyotyping demonstrated a specific pattern of gains and losses. More recently, these data have been supported by in situ hybridization and comparative genomic hybridization (CGH) on a limited number of samples. Interpretation of CGH results is complicated by the intermediate ploidy of these tumors (3-4 n for SE and 2-3 n for NS). To circumvent this problem, this particular study was undertaken. CGH was performed on 8 SE and 10 NS, after which two single chromosome normalizations were applied, one for chromosome 4 (found to be associated to the lower ploidy level of the tumor) and one for chromosome 8 (found to be associated with the higher ploidy level of the tumor) Using this modified CGH interpretation method, chromosomal regions with a similar copy number of chromosome 4 and 8 were identified as belonging to the lower and higher ploidy level, and the regions below chromosome 4 and above chromosome 8 were identified as lost or gained outside the ploidy range of the tumor, respectively. Our results are in accordance with earlier findings, however they add novel data, including comparison of SE and NS. This approach reveals relevant information about the chromosomal constitution of testicular germ cell tumors, leading to a better understanding of the pathogenesis of these tumors.

Heterogeneity in alkaline phosphatase isozyme expression in human testicular germ cell tumours: An enzyme-/immunohistochemical and molecular analysis

In humans, alkaline phosphatases are encoded by one tissue-non-specific alkaline phosphatase (TNAP) gene and three tissue-specific alkaline phosphatase genes, intestinal, placental (PLAP), and germ cell-specific alkaline phosphatase (GCAP). Although the presence of alkaline phosphatases in testicular germ cell tumours (TGCTs) of adolescents and adults has been utilized for both detection and patient monitoring, it is not known in detail which isozymes are expressed. Since alkaline phosphatase is detected in carcinoma in situ (CIS), the common precursor of all TGCTs, it might provide a marker for the early diagnosis of TGCTs. Testicular cancers of germ cell and non-germ cell origin along with testicular parenchyma with and without CIS have been analysed for the expression of the different alkaline phosphatase isozymes. Antibodies to TNAP and PLAP/GCAP showed positivity in CIS, seminoma, and embryonal carcinoma. The heterogeneous staining pattern detected in frozen tissue sections was similar to the pattern found in formalin-fixed, paraffin-embedded material, indicating a biological phenomenon and not a handling artefact. Since PLAP and GCAP cannot be distinguished using immunohistochemistry, the expression of these isozymes was studied at the molecular level using a reverse transcriptase-polymerase chain reaction (RT-PCR) approach, in combination with a primer extension assay. The results show that CIS and seminoma predominantly express GCAP, while in embryonal carcinoma the expression of GCAP versus PLAP varies. Due to the presence of alkaline phosphatase transcripts in normal testicular parenchyma, an RT-PCR-based analysis of alkaline phosphatase is not informative for the early detection of TGCTs in biopsy samples.

Lack of Bcl10 mutations in testicular germ cell tumours and derived cell lines

Aberrations within Bcl10, a gene involved in execution of apoptosis, has most recently been found in a variety of cancers, including cell lines of testicular germ cell tumours of adolescents and adults (TGCTs). To study this in more detail, we screened exons 2 and 3 of this gene for mutations in a larger series of cell lines as well as primary TGCTs by single-strand conformation polymorphism and endonuclease restriction analysis. Because no aberrations were detected, we conclude that inactivation of Bcl10 by mutation is at least far less important in the development of TGCTs than proposed.

Heterogeneous X inactivation in trophoblastic cells of human full-term female placentas

In female mammalian cells, one of the two X chromosomes is inactivated to compensate for gene-dose effects, which would be otherwise doubled compared with that in male cells. In somatic lineages in mice, the inactive X chromosome can be of either paternal or maternal origin, whereas the paternal X chromosome is specifically inactivated in placental tissue. In human somatic cells, X inactivation is mainly random, but both random and preferential paternal X inactivation have been reported in placental tissue. To shed more light on this issue, we used PCR to study the methylation status of the polymorphic androgen-receptor gene in full-term human female placentas. The sites investigated are specifically methylated on the inactive X chromosome. No methylation was found in microdissected stromal tissue, whether from placenta or umbilical cord. Of nine placentas for which two closely apposed samples were studied, X inactivation was preferentially maternal in three, was preferentially paternal in one, and was heterogeneous in the remaining five. Detailed investigation of two additional placentas demonstrated regions with balanced (1:1 ratio) preferentially maternal and preferentially paternal X inactivation. No differences in ratio were observed in samples microdissected to separate trophoblast and stromal tissues. We conclude that methylation of the androgen receptor in human full-term placenta is specific for trophoblastic cells and that the X chromosome can be of either paternal or maternal origin.

Pathogenesis of testicular germ cell tumours

Human germ cell tumours comprise a heterogeneous group of neoplasms. In the testis, three entities are distinguished, the teratomas-yolk sac tumours of the infantile testis, the seminomas and nonseminomas of adolescents and adults, and the spermatocytic seminomas. Studies on epidemiology, histology, clinical behaviour, and chromosomal constitution of these tumours support the concept of distinct entities derived from germ cells but each with a different pathogenesis. Either the teratomas of the infantile testis show no chromosomal aberrations, or display a pattern of over- and under-representation of (parts of) chromosomes as detected in the yolk sac tumours of the infantile testis. In contrast, the seminomas and nonseminomas reveal a consistent pattern of losses and gains, that is, chromosomes 11, 13 and 18, and 7, 8 and X, respectively, that is different from that found in the infantile testis teratomas and yolk sac tumours. The most consistent structural chromosomal abnormality is an isochromosome 12p. Tumours lacking i(12p) have other structural abnormalities of 12p, among them amplification of 12p11.2-p12.1. The pathogenetically relevant genes on 12p11.2-p12.1 are probably on a fragment of about 1.7 mb. Gain of 12p sequences may be related to invasive growth. Gain of chromosome 9 is the only consistent chromosomal anomaly of spermatocytic seminomas. Infantile teratomas and spermatocytic seminomas are benign tumours. Infantile yolk sac tumour is a malignant germ cell tumour. Seminomas and nonseminomas are malignant, and the most common cancer in young Caucasian males. The cure rate of seminomas and non-seminomas with radio- and chemotherapy is over 90%, which is higher than that of any other solid cancer in adults. In addition, the precursor lesions of these tumours can be treated readily, justifying efforts to develop means for early diagnosis. Finally, the pathogenetic relationship between seminomas and nonseminomas, and the available animal models for the three groups of testicular germ cell tumours are discussed.

Prognostic factors for the outcome of chemotherapy in advanced soft tissue sarcoma: an analysis of 2,185 patients treated with anthracycline-containing first-line regimens--a European Organization for Research and Treatment of Cancer Soft Tissue and Bone Sarcoma Group Study

PURPOSE

A total of 2,185 patients with advanced soft tissue sarcomas who had been treated in seven clinical trials investigating the use of doxorubicin- or epirubicin-containing regimens as first-line chemotherapy were studied in this prognostic-factor analysis.

PATIENTS AND METHODS

Overall survival time (median, 51 weeks) and response to chemotherapy (26% complete response or partial response) were the two end points. The cofactors were sex; age; performance status; prior therapies; the presence of locoregional or recurrent disease; lung, liver, and bone metastases at the time of entry onto the trial; long time period between the initial diagnosis of sarcoma and entry onto the study; and histologic type and grade.

RESULTS

Univariate analyses showed (a) a significant, favorable influence of good performance status, young age, and absence of liver metastases on both survival time and response rate, (b) a significant, favorable influence of low histopathologic disease grade on survival time, despite a significantly lower response rate, (c) increased survival time for patients with a long time period between the initial diagnosis of sarcoma and entry onto the study, despite equivalent response rates, and (d) increased survival time with liposarcoma or synovial sarcoma, a decreased survival time with malignant fibrous histiocytoma, a lower response rate with leiomyosarcoma, and a higher response rate with liposarcoma (P < .05 for all log-rank and chi2 tests). The Cox model selected good performance status (P < .0001), absence of liver metastases (P = .0001), low histopathologic grade (P = .0002), long time lapse since initial diagnosis (P = .0004), and young age (P = .0045) as favorable prognostic factors of survival time. The logistic model selected absence of liver metastases (P < .0001), young age (P = .0024), high histopathologic grade (P = .0051), and liposarcoma (P = .0065) as favorable prognostic factors of response rate.

CONCLUSION

This analysis demonstrates that for advanced soft tissue sarcoma, response to chemotherapy is not predicted by the same factors as is overall survival time. This needs to be taken into account in the interpretation of trials assessing the value of new agents for this disease on the basis of response to treatment.

Chromosomal constitution of human spermatocytic seminomas: comparative genomic hybridization supported by conventional and interphase cytogenetics

No data on the chromosomal constitution of spermatocytic seminomas are available thus far because of their rarity. Ploidy analysis performed on paraffin-embedded cases showed varying results from (near-) diploid to aneuploid. We applied comparative genomic hybridization on four snap-frozen primary spermatocytic seminomas of three different patients. Conventional cytogenetic analysis was successful in one, and "interphase cytogenetics" with centromeric region-specific probes was applied to another. The results from comparative genomic hybridization showed almost exclusively numerical chromosomal aberrations, in agreement with the data from karyotyping. Despite the limited number of cases studied, a nonrandom pattern of chromosome imbalances was detected: chromosome 9 was gained in all spermatocytic seminomas. This suggests that that this aberration plays a role in the development of this cancer. Interphase cytogenetics shows that the copy number of most chromosomes ranges from two to four, with an average of near trisomic. This constitutes the first report on the chromosomal constitution of spermatocytic seminomas.