Age-related biological features of germ cell tumors: Age-Related Biological Features of Gcts

Pediatric Extracranial Germ Cell Tumors: Review of Clinics and Perspectives in Application of Autologous Stem Cell Transplantation

Pediatric extracranial germ cell tumors (GCTs) are rare, accounting for approximately 3.5% of childhood cancers. Since the introduction of platinum-based chemotherapy, the survival rate of patients has improved to more than 80%. However, poor-risk subtypes of pediatric extracranial GCTs do not respond well to chemotherapy, leading to refractory or relapsed (R/R) diseases. For example, long-term survival rates of mediastinal GCTs or choriocarcinoma are less than 50%. According to reports in recent years for adult patients with R/R GCTs, the use of high-dose chemotherapy (HDCT) combined with autologous stem cell transplantation (ASCT) has clinical advantages; however, HDCT combined with ASCT has rarely been reported in pediatric GCTs. The R/R and poor-risk groups of pediatric GCTs could benefit from HDCT and ASCT.

Immunohistochemical Expression of Preferentially Expressed Antigen in Melanoma (PRAME) in the Uninvolved Background Testis, Germ Cell Neoplasia In Situ, and Germ Cell Tumors of the Testis

OBJECTIVES

Preferentially expressed antigen in melanoma (PRAME) has a key role in regulating pluripotency of primordial germ cells and in the development of germ cell tumors of the testis (GCTT). However, its immunohistochemical expression in normal testes and its neoplastic counterpart remain largely unknown.

METHODS

We retrospectively investigated the expression of PRAME in 26 cases of GCTT, 21 cases of germ cell neoplasia in situ (GCNIS), and 17 cases of uninvolved background testes.

RESULTS

We found that PRAME was expressed more strongly by seminomatous rather than nonseminomatous GCTT (P = .000) and by pure seminoma rather than the seminoma component of seminomatous/nonseminomatous GCTT (P = .025). In addition, GCNIS and uninvolved background testes displayed high levels of PRAME expression.

CONCLUSIONS

PRAME is an additional marker for the differential diagnosis of GCTT and could play a key role in the transition from seminomatous to nonseminomatous GCTT.

Outcomes of adolescent males with extracranial metastatic germ cell tumors: A report from the Malignant Germ Cell Tumor International Consortium

BACKGROUND

Adolescents with extracranial metastatic germ cell tumors (GCTs) are often treated with regimens developed for children, but their clinical characteristics more closely resemble those of young adult patients. This study was designed to determine event-free survival (EFS) for adolescents with GCTs and compared them with children and young adults.

METHODS

An individual patient database of 11 GCT trials was assembled: 8 conducted by pediatric cooperative groups and 3 conducted by an adult group. Male patients aged 0 to 30 years with metastatic, nonseminomatous, malignant GCTs of the testis, retroperitoneum, or mediastinum who were treated with platinum-based chemotherapy were included. The age groups were categorized as children (0 to <11 years), adolescents (11 to <18 years), and young adults (18 to ≤30 years). The study compared EFS and adjusted for risk group by using Cox proportional hazards analysis.

RESULTS

From a total of 2024 individual records, 593 patients met the inclusion criteria: 90 were children, 109 were adolescents, and 394 were young adults. The 5-year EFS rate was lower for adolescents (72%; 95% confidence interval [CI], 62%-79%) than children (90%; 95% CI, 81%-95%; P = .003) or young adults (88%; 95% CI, 84%-91%; P = .0002). The International Germ Cell Cancer Collaborative Group risk group was associated with EFS in the adolescent age group (P = .0020). After adjustments for risk group, the difference in EFS between adolescents and children remained significant (hazard ratio, 0.30; P = .001).

CONCLUSIONS

EFS for adolescent patients with metastatic GCTs was similar to that for young adults but significantly worse than for that children. This finding highlights the importance of coordinating initiatives across clinical trial organizations to improve outcomes for adolescents and young adults.

LAY SUMMARY

Adolescent males with metastatic germ cell tumors (GCTs) are frequently treated with regimens developed for children. In this study, a large data set of male patients with metastatic GCTs across different age groups has been built to understand the outcomes of adolescent patients in comparison with children and young adults. The results suggest that adolescent males with metastatic GCTs have worse results than children and are more similar to young adults with GCTs. Therefore, the treatment of adolescents with GCTs should resemble therapeutic approaches for young adults.

Germ Cell Tumors in Adolescents and Young Adults

Germ cell tumors (GCTs) are rare in childhood, representing only 3.5% of childhood cancers, but a common malignancy in adolescents and young adults (AYAs), accounting for 13.9% of neoplasms in adolescents between age 15 and 19 years. The overall outcomes of patients treated for GCTs are excellent. However, as seen in other cancers, outcomes for AYA patients are significantly worse. Understanding the reasons for this observation has led to different approaches to diagnosis, staging, and treatment. The Malignant Germ Cell International Consortium was created to bring together pediatric, gynecologic, and testicular cancer specialists to promote research initiatives and provide evidence-based approaches in the management of GCTs across different age groups. Collaboration between multiple subspecialties is essential to further understand the disease continuum, the underlying biologic characteristics, and the development of appropriate therapeutic approaches. This review focuses on the unique characteristics of patients with extracranial GCTs in the AYA group.

Chromosomal gains of 12p and 1q are not associated with inferior outcome of pediatric and adolescent germ cell tumors

BACKGROUND

Pediatric germ cell tumors (GCT) are rare and very heterogeneous neoplasms that show a high diversity in tumor biology and histology. The clinical behavior cannot be predicted based on morphology or immunohistochemistry. The aim of this study was to investigate a large number of pediatric GCT regarding chromosomal gains of 12p and 1q.

METHODS

One hundred and eighty pediatric nonseminomatous GCT, that is, mature teratomas, immature teratomas, yolk sac tumors, and mixed germ cell tumors, from three age groups were evaluated for 1q and 12p gains by fluorescence in situ hybridization in tissue micro arrays. The results were correlated with tumor biology and clinical data.

RESULTS

Eleven out of 143 GCT showed gains of 1q. In 29/157 GCT a gain of 12p was found. Prepubertal patients (≤6 years of age) more often displayed gains of 1q compared to pubertal/adolescent patients (11-17 years of age), whereas pubertal/adolescent patients showed gains of 12p most frequently. Twenty-one out of 155 patients suffered from relapse or metachronous disease. Patients with and without gains of 1q or 12p did not differ in frequency of these events. However, the likelihood of occurrence of these clinical events varied depending on the histological type of the tumor.

CONCLUSION

The biological behavior of pediatric GCT depends more on the histological type of the tumor than on the genetic aberrations examined in this study. Gains of 1q and 12p are not suitable to predict the clinical outcome of GCT in childhood. Nevertheless, both genetic alterations might be used as biomarkers to distinguish different histological types of GCT and therefore could be of diagnostic value, especially in borderline cases.

AYA testis cancer: The unmet challenge

Testis cancer is considered a rare-incidence cancer but comprises the third most common cancer diagnosed within the adolescent and young adult (AYA) years (15-39 years). Most testis cancer patients can anticipate a survival outcome in excess of 95%. However, there are subgroups of AYA patients where outcomes are considerably worse, including younger adolescents, patients with certain histological subtypes, or from certain ethnic backgrounds. For those cured with chemotherapy, the toxicity of treatment and burden of late effects is significant. Newer germ cell tumor-specific biomarkers may identify patients who do not require further treatment interventions or may detect early recurrence, potentially reducing the burden of treatment required for cure. An international collaboration for this rare tumor is creating the forum for trial design, where these biomarker research questions are embedded. Going forward, AYA testis cancer patients could benefit from having a more personalized treatment plan, tailored to risk, that minimizes the overall burden of late effects.

International testicular cancer incidence rates in children, adolescents and young adults

BACKGROUND

Testicular cancer is the most common cancer in young men in developed countries. In adults, international variation in testicular cancer incidence rates has been well-described, while previous research on pediatric and adolescent testicular cancer has been more geographically limited.

METHODS

In this analysis, we used data from the three most recent volumes of Cancer Incidence in Five Continents (CI5) and the National Cancer Institute's SEER 18 registries to compare incidence rates for testicular cancer in children (ages 0-14) and adolescents and young adults (AYA; ages 15-39).

RESULTS

We find that geographic incidence patterns in AYA are different from patterns in children under 15. In AYA, incidence is highest in Europe (137.4 per million), followed by Oceania (116.9 per million), North America (94.9 per million), South and Central America (66.5 per million), and lowest in Asia (27.1 per million). In contrast, childhood incidence is highest in Asia (4.2 per million) and South America (5.0 per million) and lowest in Europe (2.1 per million) and North America (2.5 per million). In the United States, patterns in incidence rates in racial and ethnic groups mirror international rates.

CONCLUSION

These differences in incidence rate variations in pediatric and AYA testicular cancer are intriguing and may aid in understanding the different etiologies of testicular cancer by age group.

Comparison of carboplatin versus cisplatin in the treatment of paediatric extracranial malignant germ cell tumours: A report of the Malignant Germ Cell International Consortium

PURPOSE

To compare the outcomes of paediatric and adolescent extracranial malignant germ cell tumour (GCT) patients treated with either carboplatin or cisplatin on clinical trials conducted by the Children's Oncology Group (COG) and the Children's Cancer and Leukaemia Group (CCLG).

METHODS

The Malignant Germ Cell International Consortium (MaGIC) has created a database of the GCT clinical trials conducted since 1983 by COG (United States, Canada and Australia), which used cisplatin-based regimens, and by CCLG (United Kingdom), which used carboplatin-based regimens. Using the parametric cure model, this study compared the overall 4-year event-free survival (EFS), stratified by age, stage, site and the a-priori defined MaGIC 'risk' groups: standard risk ((SR) 1 (EFS >80%; age <11 years), SR2 (EFS >80%, age ≥ 11y) and poor risk (PR) (EFS ≤ 70%, age ≥ 11y).

RESULTS

Cisplatin-based therapy was used in 620 patients; carboplatin was used in 163 patients. In the overall multivariate cure model, the two regimens did not differ significantly (cisplatin: 4-year EFS 86%; 95% confidence interval (CI) 83-89% versus carboplatin 4-year EFS 86%; 95% CI 79-90%; p = 0.87). No significant differences were noted in stratified analyses by site, stage, age and MaGIC risk groups: SR1 (p = 0.20), SR2 (p = 0.55) or PR (p = 0.72) patients.

CONCLUSIONS

In these trials conducted contemporaneously, there is no significant difference in outcome observed overall, or any subset of patients, who were treated with regimens containing cisplatin versus carboplatin These results suggested sufficient equipoise to justify a randomised trial to evaluate the effectiveness of carboplatin versus cisplatin in the treatment of children, adolescents and young adults with standard risk GCT, which is currently underway.

Is carboplatin-based chemotherapy as effective as cisplatin-based chemotherapy in the treatment of advanced-stage dysgerminoma in children, adolescents and young adults?

OBJECTIVE

Dysgerminoma is the most common malignant ovarian germ cell tumor (GCT) with peak incidence during adolescence and young adulthood. Current standard of care for patients with disease that has spread outside of the ovary (advanced-stage) utilizes platin-based chemotherapy regimens. The study objective was to compare clinical outcomes between platin-based (carboplatin versus cisplatin) strategies across all age groups (children < 11 years (y), adolescents = 11-25 y and young adult women > 25 y) for advanced-stage dysgerminoma.

METHODS

The Malignant Germ Cell Tumor International Consortium (MaGIC) pooled data from six GCT trials (3 = pediatric, 3 = adult) conducted internationally by pediatric and gynecologic oncology clinical trial organizations (CTOs) between 1983 and 2009. Newly diagnosed patients, with advanced-stage (FIGO IC-IV) dysgerminoma, who received either carboplatin- or cisplatin-based chemotherapy were eligible for analysis.

RESULTS

126 eligible patients were identified; 56 patients (38 = pediatric, 18 = adult) received carboplatin-based and 70 patients (50 = pediatric, 20 = adult) received cisplatin-based chemotherapy. Mean age was 20 y (range = 6-46 y). The median follow-up was 10.3 y (range = 0.17-21.7 y). The five-year event-free survival (EFS₅) and overall survival (OS₅) was 0.94 (95%CI, 0.88-0.97) and 0.96 (95%CI, 0.91-0.99) respectively. Survival outcomes were comparable between carboplatin-(EFS₅ = 0.96 (95%CI, 0.85-0.99), OS₅ = 0.96 (95%CI, 0.85-0.99)) and cisplatin-(EFS₅ = 0.93 (95%CI, 0.83-0.97), OS₅ = 0.96 (95%CI, 0.87-0.99)) based regimens. Across three age groups, comparison of the EFS₅ (<11 y = 0.1, 11-25 y = 0.91 (95%CI, 0.82-0.96), >25 y = 0.97 (95%CI, 0.81-0.99)) and OS₅ (<11 y = 0.1, 11-25 y = 0.95 (95%CI, 0.87-0.99), >25 y = 0.97 (95%CI, 0.81-0.99)) did not demonstrate any statistically significant differences in outcomes.

CONCLUSIONS

Patients diagnosed with dysgerminoma have an excellent OS, across all ages, even in the context of metastatic disease. Data from three large CTOs supports the investigation of carboplatin-based regimens in the frontline treatment of all patients with advanced-stage dysgerminoma to minimize treatment-related toxicities.

What is new in pediatric surgical oncology?

PURPOSE OF REVIEW

As pediatric oncology has become more complex, designing and maintaining pediatric surgical protocols require greater expertise. The primary purpose of this review is to summarize the changes in protocols and new study findings, which have changed surgical practice for children with solid tumors.

RECENT FINDINGS

The most common solid tumors treated by surgery are reviewed. There are new methods of surgical techniques such as the use of sentinel lymph node techniques for the assessment of lymph nodes in pediatric sarcoma. New studies showing excellent outcomes for the nonoperative treatment for young patients with neuroblastoma are discussed. Surgical quality with the prevention of tumor rupture and the assessment of lymph nodes is essential for good outcomes in patients with Wilm's tumor. The international collaborations within germ cell and liver tumors have provided excellent new study regimens and welcomed a new era of studies that are robust and have the power to change the outcomes for these rare tumors.

SUMMARY

Surgical practice is evolving with the molecular advances in pediatric oncology. Technical advances and quality improvement endeavors to ensure protocol adherence are essential. International partnerships have allowed for greater advances particularly for rare tumors and improve overall surgical outcomes.

Pediatric malignant germ cell tumors: A comparison of the neuro-oncology and solid tumor experience

Malignant germ cell tumors (GCT) arise from abnormal migration of primordial germ cells and are histologically identical whether they occur inside or outside the central nervous system (CNS). However, the treatment strategy for GCTs varies greatly depending on the location of the tumor. These differences are in part due to the increased morbidity of surgery in the CNS but may also reflect differential sensitivity of the tumors to chemotherapy and radiation therapy (RT) or not-yet-understood biologic differences between these tumors. Historically, specialists caring for extracranial and intracranial GCT in the United States have practiced separately without much cross communication. The focus of this review is a discussion of differences between the management of CNS and extra-CNS GCTs and opportunities for collaboration and future research.

The influence of age and other prognostic factors associated with survival of ovarian immature teratoma - A study of 1307 patients

OBJECTIVE

To determine impact of age and other prognostic factors on the survival of ovarian immature teratoma (IT) patients.

METHODS

Data obtained from the SEER database between 1973 and 2012. Kaplan-Meier methods and multivariate Cox regression models were used for statistical analyses.

RESULTS

Of 1307 patients (median: 24years; range: 0-93), 78%, 5%, 13%, 4% were stages I, II, III and IV, respectively. 25%, 35%, and 40% had grades 1, 2, and 3. Whites were less likely to be diagnosed, and Asians had a nearly 3-fold higher proportion of IT compared to the proportion of Asians in the U.S. census. The 5-year disease-specific survival (DSS) was 91.2%. Those with stages I, II, III and IV disease had survivals of 99.7%, 95%, 81%, and 71.8% (p<0.001) and grades 1, 2, and 3 had DSS of 98.7%, 95.8%, and 91% (p<0.001), respectively. Of those who underwent fertility-preserving surgery, the DSS was 98.8%. Over time from 1973 to 1986, to 1987-1999, to 2000-2012, the survivals were 76.4%, 92.8%, and 94.7% (p<0.001). Of stage I patients, no patient <18years (n=214, used as adult cutoff) and 2 of 283 patients >18years died of cancer, with corresponding 5years DSS of 100% vs. 99.6% (p>0.05). Older age (by year, HR: 1.05; 95% CI: 1.04-1.06; p<0.0001) and higher stage (HR: 11.52; 95% CI: 4.08-32.48; p<0.0001) were independent factors indicating poorer survival.

CONCLUSION

The outcome of patients with stage I disease was excellent at 99.7%, with children and adults having corresponding survivals of 100% and 99.6%.

Risk of second gonadal cancers in women and children with germ cell tumors

BACKGROUND

Men with testicular cancer have an increased risk of developing cancer in the contralateral testis, but the risks of second gonadal cancers (SGCs) in women and children treated for germ cell tumors (GCTs) have not previously been quantified.

METHODS

The incidence of SGCs was ascertained in patients who had survived for at least 1 year after GCT diagnosis using data from the Surveillance, Epidemiology, and End Results SEER 9 registries (1980-2012). Relative risks of SGCs were estimated separately for boys, women, and girls compared with men based on Poisson regression analysis.

RESULTS

The cohort included 21,546 individuals (1116 boys, 827 women, 622 girls, and 18,981 men). A total of 25 SGCs were identified in boys, 1 in women, and 2 in girls compared with 254 in men. The risk of SGC in postpubertal boys (aged ≥10 years) was comparable to that of adult men (boys: standardized incidence ratio, 15.90; 95% confidence interval, 10.29-23.47; men: standardized incidence ratio, 10.88; 95% confidence interval, 9.58-12.30). However, no SGCs were observed in boys who were diagnosed with a testicular GCT before age 10 years (N = 179). An elevated risk of SGC was also not observed for women or girls.

CONCLUSIONS

The apparent lack of an SGC in prepubertal boys suggests that susceptibility is either age-dependent and/or histology-dependent. The sex differences in the risk of SGC suggest differences in the etiology of ovarian versus testicular GCT. The finding that the risk of SGCs in postpubertal boys is similar to that observed in men indicates that long-term follow-up for SGC is warranted in postpubertal boys. Cancer 2016;122:2076-82. © 2016 American Cancer Society.

Intratubular germ cell neoplasia of the testis: a brief review

Germ cell tumors of the testis may be divided into 3 broad categories according to age at presentation. The tumors in the pediatric age group include teratoma and yolk sac tumor. These tumors are generally not associated with convincing intratubular neoplasia. The second group consists of tumors presenting in third and fourth decade of life and include seminoma, embryonal carcinoma, yolk sac tumor, choriocarcinoma, and teratoma as well as mixed germ cell tumors. The precursor cell for these tumors is an abnormal gonocyte that fails to differentiate completely into spermatogonia. These abnormal cells stay dormant in the gonad during intrauterine life as well as infancy and childhood, but undergo proliferation during puberty and can be identified as intratubular germ cell neoplasia unclassified (IGCNU). These tumor cells continue to manifest protein expression pattern that resembles primitive germ cells (PLAP, c-KIT, OCT3/4). After a variable interval following puberty, IGCNU cells may acquire ability to penetrate the seminiferous tubules and present as an overt germ cell tumor. Acquisition of isochrome 12 and other genetic abnormalities are usually associated with this transition. The level of DNA methylation generally determines the phenotype of the germ cell tumor. The third type of germ cell tumors is spermatocytic seminoma, which is a rare tumor encountered later in life usually in fifth and sixth decade. The cell of origin of this tumor is probably postpubertal mature spermatogonia which acquire abnormal proliferative capability probably due to gain of chromosome 9 resulting in activation and amplification of genes such as DMRT1. The tumor cells manifest many of the proteins normally expressed by mature sperms such as VASA, SSX2, and occasionally OCT2. Although spermatocytic seminoma may also have an intratubular growth phase, it completely lacks features of IGCNU.

Biology of childhood germ cell tumours, focussing on the significance of microRNAs

Genomic and protein-coding transcriptomic data have suggested that germ cell tumours (GCTs) of childhood are biologically distinct from those of adulthood. Global messenger RNA profiles segregate malignant GCTs primarily by histology, but then also by age, with numerous transcripts showing age-related differential expression. Such differences are likely to account for the heterogeneous clinico-pathological behaviour of paediatric and adult malignant GCTs. In contrast, as global microRNA signatures of human tumours reflect their developmental lineage, we hypothesized that microRNA profiles would identify common biological abnormalities in all malignant GCTs owing to their presumed shared origin from primordial germ cells. MicroRNAs are short, non-protein-coding RNAs that regulate gene expression via translational repression and/or mRNA degradation. We showed that all malignant GCTs over-express the miR-371-373 and miR-302/367 clusters, regardless of patient age, histological subtype or anatomical tumour site. Furthermore, bioinformatic approaches and subsequent Gene Ontology analysis revealed that these two over-expressed microRNAs clusters co-ordinately down-regulated genes involved in biologically significant pathways in malignant GCTs. The translational potential of this finding has been demonstrated with the detection of elevated serum levels of miR-371-373 and miR-302/367 microRNAs at the time of malignant GCT diagnosis, with levels falling after treatment. The tumour-suppressor let-7 microRNA family has also been shown to be universally down-regulated in malignant GCTs, because of abundant expression of the regulatory gene LIN28. Low let-7 levels resulted in up-regulation of oncogenes including MYCN, AURKB and LIN28 itself, the latter through a direct feedback mechanism. Targeting LIN28, or restoring let-7 levels, both led to effective inhibition of this pathway. In summary, paediatric malignant GCTs show biological differences from their adult counterparts at a genomic and protein-coding transcriptome level, whereas they both display very similar microRNA expression profiles. These similarities and differences may be exploited for diagnostic and/or therapeutic purposes.