Abnormal infantile germ cells and development of carcinoma-in-situ in maldeveloped testes: a stereological and densitometric study

Germ cells positive for PLAP and c-Kit in 11-16 year old normal boys with ongoing spermatogenesis

INTRODUCTION

Positive staining of testicular germ cells for PLAP and c-Kit beyond infancy may be associated with the presence of GCNIS (Germ Cell Neoplasia In Situ). We recently reported our findings of positive staining of normal, infantile germ cells for PLAP, and c-Kit up to 2 years of age, contrary to previous studies. The present study aims to elucidate whether otherwise normal testes of boys undergoing puberty express PLAP, c-Kit, Oct3/4, or D2-40.

MATERIALS AND METHODS

Biopsies were taken from 31 boys (11.5-16.5 years of age, mean and median of 13.5 years), who underwent surgery either for torsion of the testis (15) or a history suspicious of intermittent torsion of the testis (16). 21 were biopsied on both sides, making a total of 52 biopsies. Four testes were necrotic. The biopsies were fixed in Stieve's medium, cut into 2 μm sections, and mounted on coated slides. One slide was processed for H-E, and the others incubated with primary antibody for PLAP, c-Kit, D2-40, and Oct3/4.

RESULTS

87% of the boys stained positive for both PLAP and c-Kit. None were positive for either D2-40 or Oct3/4. None had any histological features characteristic of GCNIS. Only two boys showed no signs of having initiated spermatogenesis. Those positive for PLAP were likewise for c-Kit, and vice versa, except 2; one boy, 13 years, was positive for PLAP, but negative for c-KIT, another, 16 years, was negative for PLAP and positive for c-Kit. Three boys stained positive for PLAP and c-Kit on the right side, and negative on the left. One boy was negative for c-Kit on the right side, positive on the left, and positive for PLAP bilaterally.

CONCLUSION

Positive staining of testicular germ cells for PLAP and c-Kit seems to be a normal finding in boys not having completed puberty. Rather than indicating pre-malignant transformation, the positivity is indicative of an ongoing maturational process of the germ cells.

The in vivo role of androgen receptor SUMOylation as revealed by androgen insensitivity syndrome and prostate cancer mutations targeting the proline/glycine residues of synergy control motifs

The androgen receptor (AR) mediates the effects of male sexual hormones on development and physiology. Alterations in AR function are central to reproductive disorders, prostate cancer, and Kennedy disease. AR activity is influenced by post-translational modifications, but their role in AR-based diseases is poorly understood. Conjugation by small ubiquitin-like modifier (SUMO) proteins at two synergy control (SC) motifs in AR exerts a promoter context-dependent inhibitory role. SC motifs are composed of a four-amino acid core that is often preceded and/or followed by nearby proline or glycine residues. The function of these flanking residues, however, has not been examined directly. Remarkably, several AR mutations associated with oligospermia and androgen insensitivity syndrome map to Pro-390, the conserved proline downstream of the first SC motif in AR. Similarly, mutations at Gly-524, downstream of the second SC motif, were recovered in recurrent prostate cancer samples. We now provide evidence that these clinically isolated substitutions lead to a partial loss of SC motif function and AR SUMOylation that affects multiple endogenous genes. Consistent with a structural role as terminators of secondary structure elements, substitution of Pro-390 by Gly fully supports both SC motif function and SUMOylation. As predicted from the functional properties of SC motifs, the clinically isolated mutations preferentially enhance transcription driven by genomic regions harboring multiple AR binding sites. The data support the view that alterations in AR SUMOylation play significant roles in AR-based diseases and offer novel SUMO-based therapeutic opportunities.

Androgen insensitivity syndrome

Over the past four years, major advances in the understanding of the aetiology and pathogenesis of the androgen insensitivity syndrome (AIS) have occurred. This review aims to summarize current information on clinical, diagnostic, therapeutic and molecular aspects of AIS.

The expression and function of androgen receptor coactivator p44 and protein arginine methyltransferase 5 in the developing testis and testicular tumors

PURPOSE

The role of androgen receptor coactivators in testicular development and cancer formation is unclear. p44/Mep50 was identified as an androgen receptor coactivator that functions in a complex with protein arginine methyltransferase 5. We studied the expression of p44 and protein arginine methyltransferase 5 in developing fetal testis and adult testicular tumors, including seminomas and Leydig cell tumors.

MATERIALS AND METHODS

A total of 30 human fetal testes from abortuses at a gestational age of 10 to 40 weeks, 33 human seminomas and 11 human Leydig cell tumors were retrieved from the archives of the departments of pathology. Immunohistochemistry was performed with affinity purified p44 and IgG purified protein arginine methyltransferase 5 polyclonal antibodies.

RESULTS

Protein arginine methyltransferase 5 and p44 were expressed predominantly as nuclear proteins in fetal Leydig cells and human adult nonneoplastic testes, including germ cells and Leydig cells, while they were expressed in the cytoplasm of germ cells of the fetal testis. Expression was strongest in the fetal testis during the second trimester. Compared to adult nonneoplastic testes, human seminoma and Leydig tumor cells showed a marked decrease in nuclear expression of p44 and protein arginine methyltransferase 5 with a concomitant marked increase in cytoplasmic expression of these proteins. Furthermore, average testicular size was increased by 29% in p44(+/-) heterzygotic mice.

CONCLUSIONS

These results suggest distinct functions of the nuclear and the p44/protein arginine methyltransferase 5 complexes in the developing fetal testis and in the oncogenesis of testicular tumors. Further studies are needed to confirm the functional relevance of these findings.

Linkage between androgen receptor gene CAG trinucleotide repeat length and testicular germ cell cancer histological type and clinical stage

Sex hormones and/or gonadotropins may play a crucial role in the development of testicular germ cell cancer (TGCC). A direct link between this malignancy and endocrine factors has not been confirmed. We tested whether CAG and GGN repeats of the androgen receptor gene (AR) play a role in the aetiology or pathogenesis of TGCC. Eighty-three TGCC patients and 220 controls were included. Mean CAG or GGN lengths did not differ between the TGCC cases and controls. The proportion of males with CAG lengths above 25, indicative of reduced androgen sensitivity, was significantly lower among patients with pure seminomas and in the combined group of seminomas and mixed tumours compared with non-seminomas and controls. The median CAG length was higher if the tumour was metastasing at diagnosis. This is the first study showing an association between the AR polymorphism and histological type as well as the progression rate of TGCC.

Management of recurrence and follow-up strategies for patients with seminoma and selected high-risk groups

Seminoma is characterized by high sensitivity to both radiation and chemotherapy. Localized recurrences in the retroperitoneum after surveillance for stage I can be treated with radiotherapy; however, multiple or large bulky retroperitoneal recurrences or systemic metastasis requires cisplatin-based chemotherapy. Salvage chemotherapy for those who recur after initial CR to induction chemotherapy is based on ifosfamide- and cisplatin-containing regimens. Incomplete response or failure after induction chemotherapy requires high-dose chemotherapy and stem cell rescue. Patients with seminoma need long-term follow-up because of the possibility of late recurrence and the risk of a second primary tumor.

Neoplastic potential of germ cells in relation to disturbances of gonadal organogenesis and changes in karyotype

The study consisted of 46 intersexual patients who underwent gonadectomy at the age of 3 months to 19 years because of gonadal dysgenesis (GD; 40 cases) or true hermaphroditism (bisexual gonads; 6 cases). In patients with GD, the incidence of the 46,XY karyotype was 67.5%, whereas the remaining patients exhibited numerical and structural aberrations of sex chromosomes (NSASs), and all patients with bisexual gonads revealed NSAS. Seminoma was diagnosed in 1 patient with the 46,XY karyotype and pure GD (streak gonads). Intratubular carcinoma in situ (CIS) appeared as an exclusive lesion in 61.5% of 13 patients with mixed GD, in 54% of 11 patients with partial GD (bilateral testes), in 16.7% of 6 patients with bisexual gonads, and in none of 13 patients with pure GD. CIS also appeared in tubules in the vicinity of sex cord-derived tumors (gonadoblastoma nests and unclassified mixed germ cell-sex cord-stromal tumor; MGCSCST) and within the tumors. In 3 patients, gonadoblastoma replaced the whole bilateral gonads and is referred to as gonadoblastoma-only GD. The incidence of neoplastic lesions (mostly bilateral) was 90.9% in patients with partial GD, 76.9% (mostly unilateral) in patients with mixed GD, 23.1% (unilateral) in patients with pure GD, and 16.7% (unilateral) in patients with bisexual gonads. Disregarding types of disturbances of gonadal organogenesis, the incidence of lesions was 71.4% in 28 patients with the 46,XY karyotype and 35.3% in 17 patients with NSAS. We conclude, first, that NSAS is not a prerequisite for the appearance of GD and GD is more frequently associated with the 46,XY karyotype. Second, the spectrum of germ cell neoplastic lesions in GD is wider than reported. Besides germ cell carcinoma, CIS, and gonadoblastoma nests, the spectrum also includes a tumor of gonadoblastoma-only in cases of GD and MGCSCST. Third, the incidence of neoplastic lesions is related more to the severity of the disturbances of gonadal organogenesis than it is to aberrations in sex chromosomes. Fourth, less disturbed testicular organogenesis predisposes these patients more toward germ cell neoplastic lesions, which suggests that the testicular environment of a dysgenetic gonad plays an important role in germ cell neoplasia initiation, maintenance, or both.

Double immunolabeling by the RBM and the PLAP markers for identifying intratubular (in situ) germ cell neoplasia of the testis

Identification of intratubular germ cell neoplasia (carcinoma in situ, CIS) of the testis is a diagnostic challenge, and markers are sorely needed to assist in accurately identifying the lesion. RNA-binding motif (RBM) protein, encoded by the Y chromosome, is expressed exclusively and consistently in differentiated male germ cells, while it is absent in neoplastic germ cells. Another immunohistochemical marker, placental alkaline phosphatase (PLAP), is commonly used for the detection of undifferentiated germ cells. The current study demonstrates that simultaneous use of the immunohistochemical markers, RBM and PLAP, by double immunolabeling enhances the accuracy of diagnosing CIS, a preinvasive testicular neoplasm.

[Testicular intraepithelial neoplasms (TIN). An indication for radiotherapy?]

BACKGROUND

Testicular intraepithelial neoplasia (TIN), synonymous for carcinoma in situ of the testis, is a rarely observed preinvasive neoplasia located within the germinative epithelium. According to the current knowledge of the biology of TIN, it is the common precursor of all testicular germ cell neoplasms except spermatocytic seminoma.

MATERIAL AND METHODS

This report provides a review of histopathology, epidemiology and diagnostic procedures for TIN and discusses the therapeutic options with particular respect to radiooncological aspects.

RESULTS

TIN has a 70% rate of progression to invasive cancer within 7 years. Depending on the individual therapeutic setting surgery, chemotherapy and radiotherapy are alternative treatment modalities. In case of TIN in a single testis or bilateral TIN, local radiotherapy is the standard procedure. With 20 Gy recommended as standard dose in Germany, radiotherapy yields safe eradication of TIN. However, some of the patients show significantly reduced synthesis of testicular androgens. With respect to sporadic reports in the literature, total doses well below 20 Gy might be equally efficient to treat TIN safely. Yet, up to date neither the minimum dose for efficient treatment nor the toxicity profile after consecutive chemo-radiotherapy has been established.

CONCLUSIONS

The currently recommended standard dose of 20 Gy in Germany is probably in excess of the minimum dose needed for safe eradication of TIN. Thus, new radiooncological strategies should aim at reducing the total dose of treatment in order to minimize late side effects while maintaining the high efficacy of radiotherapy. This topic is under investigation in a multicenter clinical trial.

Morphology and immunohistochemistry of carcinoma in situ adjacent to testicular germ cell tumours in adults and children: implications for histogenesis

Observations differ on the pre-invasive malignant lesions associated with the various categories of testicular germ cell tumours. Such lesions have been found to be similar in appearance and are assumed to be composed of multipotent cells, or conversely a distinctive pre-invasive stage has been reported in association with each form of germ cell neoplasm. This study was undertaken to see whether distinctive morphological and immunohistochemical features of carcinoma in situ adjacent to various categories of germ cell tumours could be established. Carcinoma in situ adjacent to seminomas, teratomas and mixed germ cell tumours in 18 adults was indistinguishable morphologically. Placental alkaline phosphatase was demonstrated immunohistochemically but vimentin and low molecular weight cytokeratins were uniformly absent in these abnormal germ cells from all three groups. These findings support the concept of a multipotent pre-invasive malignant cell for both seminoma and teratoma in the adult. Carcinoma in situ was not seen adjacent to 15 spermatocytic seminomas, nor was placental alkaline phosphatase demonstrated in tubules adjacent to these tumours. These negative findings are additional evidence that spermatocytic seminoma differs from classical seminoma in its histogenesis. Carcinoma in situ, as defined morphologically and immunohistochemically in adults, was not identified adjacent to yolk sac tumours and differentiated teratomas in 20 prepubertal testes. The possibility that pre-invasive malignancy in children may not resemble that in adults must be considered when assessing the malignant potential of cryptorchid testes on biopsies taken during orchidopexy.

Stereological estimates of nuclear volume in normal germ cells and carcinoma in situ of the human testis

Carcinoma in situ of the testis may appear many years prior to the development of an invasive tumour. Using point-sampled intercepts, base-line data concerning unbiased stereological estimates of the volume-weighted mean nuclear volume (nuclear vV) were obtained in 50 retrospective serial testicular biopsies from 10 patients with carcinoma in situ. All but two patients eventually developed an invasive growth. Testicular biopsies from 10 normal adult individuals and five prepubertal boys were included as controls. Nuclear vV in testicular carcinoma in situ was significantly larger than that of morphologically normal spermatogonia (2P = 1.0 x 10(-19)), with only minor overlap. Normal spermatogonia from controls had, on average, smaller nuclear vV than morphologically normal spermatogonia in biopsies with ipsi- or contra-lateral carcinoma in situ (2P = 5.2 x 10(-3)). No difference in nuclear vV was found in carcinoma in situ with or without co-existing invasion, and no characteristic pattern of nuclear vV was disclosed by following the lesion in serial biopsies over time from individual patients. Estimation of nuclear vV may represent an adjuvant tool in morphologically puzzling cases of testicular carcinoma in situ, but the prognostic value requires further evaluation in larger series of patients.

XO/XY mosaicism in phenotypic males

Eight cases of 45 XO/46 XY mosaicism are described: four were phenotypic males. Karyotyping should be performed more frequently in short boys as growth hormone treatment and testicular biopsy, to screen for carcinoma in situ, are likely to be beneficial.

Monoclonal antibody 43-9F as a sensitive immunohistochemical marker of carcinoma in situ of human testis

Invasive germ cell cancer can be prevented if the neoplasia is diagnosed at the stage of carcinoma in situ (CIS). In routine histologic examination CIS may be overlooked, particularly in prepubertal individuals. The detection of this early malignancy may be greatly facilitated by use of immunohistochemical staining. The authors investigated the sensitivity of an immunohistochemical staining procedure with monoclonal antibody 43-9F in detection of CIS. Testicular specimens from 19 adult and two prepubertal individuals with CIS were tested. Positive staining reaction on the surface of malignant germ cells was encountered in all 21 specimens with CIS. The epithelial cells of the excretory ducts between testis and epididymis, including rete testis and canaliculi efferentes, reacted also positively with 43-9F. No staining was observed in nonmalignant testicular cells including Sertoli cells or Leydig cells in any of these samples or in testicular biopsy specimens from 27 adult and 11 prepubertal subjects without evidence of testicular neoplasia. Monoclonal antibody 43-9F was also found to react with cells of all four tested invasive testicular germ cell tumors. Thus, the monoclonal antibody 43-9F is a sensitive immunohistochemical marker of CIS germ cells and may also be of potential value in detection of invasive testicular cancer.