Imaging of pediatric ovarian neoplasms

Surgical management of ovarian masses in children and adolescents: experience of an academic institution in France

PURPOSE

Surgical management of ovarian masses in girls still challenging. The aim of the study is to report an 8-year experience in managing children with ovarian masses, and to demonstrate the advantages and the limitations of laparoscopy for such lesions.

METHODS

Data of girls aged less than 18 years operated because of an ovarian mass between January 2015 and February 2023 were retrospectively reviewed. Patients were divided into two groups: group A including children operated by laparoscopy, and Group B of patients who underwent open surgery.

RESULTS

Eighty-eight children were enrolled. Laparoscopy was performed in 56 patients (63.6%). Group A patients had smaller tumor size (53.6±38.5 vs. 122.2±75.4 mm, P<0.0001), shorter operative time (50.4±20.3 vs. 71.5±36.5 min, P = 0.004), reduced length of hospital stay (1.4±1.1 vs. 3±2.3 days, P<0.0001), and absence of postoperative complications. Only 3 cases (5.7%) of recurrence were seen exclusively within patients followed for benign tumors during a mean follow-up period of 4.6±3 years.

CONCLUSION

Laparoscopy should be done in benign ovarian lesions or/and if a torsion is seen. For tumors at high risk of malignancy, laparoscopy can be performed to establish a clear macroscopic diagnosis, for staging of the disease, and resection of small tumors. Conversion to open surgery is indicated in case of doubt.

Diagnostic Performance of Magnetic Resonance Imaging for Pediatric Ovarian Neoplasms: A Multi-Institutional Review

STUDY OBJECTIVE

To assess the diagnostic performance of MRI to predict ovarian malignancy alone and compared with other diagnostic studies.

METHODS

A retrospective analysis was conducted of patients aged 2-21 years who underwent ovarian mass resection between 2009 and 2021 at 11 pediatric hospitals. Sociodemographic information, clinical and imaging findings, tumor markers, and operative and pathology details were collected. Diagnostic performance for detecting malignancy was assessed by calculating sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for MRI with other diagnostic modalities.

RESULTS

One thousand and fifty-three patients, with a median age of 14.6 years, underwent resection of an ovarian mass; 10% (110/1053) had malignant disease on pathology, and 13% (136/1053) underwent preoperative MRI. MRI sensitivity, specificity, PPV, and NPV were 60%, 94%, 60%, and 94%. Ultrasound sensitivity, specificity, PPV, and NPV were 31%, 99%, 73%, and 95%. Tumor marker sensitivity, specificity, PPV, and NPV were 90%, 46%, 22%, and 96%. MRI and ultrasound concordance was 88%, with sensitivity, specificity, PPV, and NPV of 33%, 99%, 75%, and 94%. MRI sensitivity in ultrasound-discordant cases was 100%. MRI and tumor marker concordance was 88% with sensitivity, specificity, PPV, and NPV of 100%, 86%, 64%, and 100%. MRI specificity in tumor marker-discordant cases was 100%.

CONCLUSION

Diagnostic modalities used to assess ovarian neoplasms in pediatric patients typically agree. In cases of disagreement, MRI is more sensitive for malignancy than ultrasound and more specific than tumor markers. Selective use of MRI with preoperative ultrasound and tumor markers may be beneficial when the risk of malignancy is uncertain.

CONCISE ABSTRACT

This retrospective review of 1053 patients aged 2-21 years who underwent ovarian mass resection between 2009 and 2021 at 11 pediatric hospitals found that ultrasound, tumor markers, and MRI tend to agree on benign vs malignant, but in cases of disagreement, MRI is more sensitive for malignancy than ultrasound.

Imaging of pediatric ovarian tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper

Ovarian tumors in children are uncommon. Like those arising in the adult population, they may be broadly divided into germ cell, sex cord, and surface epithelium subtypes; however, germ cell tumors comprise the majority of lesions in children, whereas tumors of surface epithelial origin predominate in adults. Diagnostic workup, including the use of imaging, requires an approach that often differs from that required in an adult. This paper offers consensus recommendations for imaging of pediatric patients with a known or suspected primary ovarian malignancy at diagnosis and during follow-up.

Clinical and Computed Tomographic Features of Ovarian Lesions in Infants, Children, and Adolescents: A Series of 222 Cases

STUDY OBJECTIVE

To investigate the clinical and computed tomography (CT) characteristics of ovarian lesions in infants, children, and adolescents.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective analysis of the clinical and CT data was performed in 222 patients who were 20 years or younger with ovarian lesions. Patients' age, medical history, symptoms, tumor marker levels, and CT imaging findings were recorded.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Identification of the clinical and CT features of ovarian lesions in infants, children, and adolescents.

RESULTS

A total of 136 patients had abdominal pain, and 73 patients had palpable abdominal mass. The β-HCG was elevated in 4 and AFP was elevated in 16 of the 222 cases. A total of 235 lesions were found in 222 cases, including 75 non-neoplastic and 160 neoplastic lesions. Ovarian cyst exhibited homogeneous low density. The torsion of a normal-sized ovary demonstrated mild or no enhancement. The torsion associated with an ovarian mass demonstrated a thickened, hyperdense wall. Mature teratoma presented as a cystic mass, with bulk fat and coarse calcification. Immature teratoma appeared as a solid mass with foci of fat and fine calcification. Yolk sac tumor was shown as cystic-solid mass with intense enhancement of solid component. Wall and septation of benign epithelial tumors were relatively uniform in thickness; mural nodule was detected in borderline tumor; and malignant epithelial tumor was predominantly a solid mass with intense enhancement.

CONCLUSION

Ovarian cyst is the most common non-neoplastic lesion. Torsion of a normal-sized ovary was the second most common non-neoplastic lesion, almost always causing abdominal pain. Germ cell tumor has the highest incidence among neoplastic lesions. Fat and calcification are highly specific for germ cell tumor. The elevation of AFP and HCG levels in serum indicates germ cell tumor. Ovarian epithelial tumor is usually large, benign, and predominantly cystic. The combination of clinical and imaging features is helpful for correct diagnosis.

The role of preoperative imaging and tumor markers in predicting malignant ovarian masses in children

PURPOSE

To investigate the clinicopathololgic characteristics and the predicting value of preoperative imaging and tumor markers in children with ovarian masses.

METHODS

Patients admitted in Shanghai children's hospital with ovary neoplasms between 2010.01 and 2015.12 were retrospectively analyzed. The medical records including age at operation, presentation of symptoms and signs, tumor marker, imaging, pathology, tumor diameter and surgical choice were reviewed. All data were analyzed using SPSS 17.0 RESULTS: A total of 139 patients were included, among which 116 were benign neoplasms and 23 malignant tumors. There was significance difference relation with the tumor diameter, character, torsion and tumor markers, but not the age, position, calculi, and symptoms. The risk factors include tumor diameters ≥ 10 cm, the odds ratio (OR) was 11, 95% confidence interval (CI) was 3-36, solid/complex tumor (OR 6, 95% CI 2, 14) and positive in tumor markers (OR 84, 95% CI 20, 345). Among the patients with benign neoplasms, 77 of them had laparoscopic ovarian cystectomy while 23 patients with malignant tumors had salpingo-oophorectomy and omentum resection.

CONCLUSION

Preoperative imaging and tumor markers could help identifying the malignant ovarian masses in children. If tumor diameter ≥ 10 cm, solid/complex in imaging and tumor markers abnormal, a radical resection is mandatory; otherwise, an ovarian-sparing surgery is recommended.

Imaging in pediatric ovarian tumors

The spectrum of ovarian tumors in the pediatric population differs significantly from that in adults. Germ cell tumors are the predominant class of ovarian tumors in children, whereas epithelial tumors are the most common in adults. Ultrasonography is the modality of choice for the initial evaluation of pediatric ovarian tumors. Determining the diagnosis based on imaging may prove difficult, and combining the imaging findings with the clinical scenario is very helpful in reaching a differential diagnosis during clinical practice. We will discuss the spectrum of ovarian neoplasms in the pediatric population and describe their clinical, pathologic, and imaging characteristics. A few unique entities related to ovarian tumors, such as growing teratoma syndrome, anti-N-methyl-D-aspartate receptor encephalitis, and hereditary ovarian tumor syndromes, are also discussed. In addition, we will review several entities that may mimic ovarian neoplasms as well as their distinct imaging features.

MR imaging in discriminating between benign and malignant paediatric ovarian masses: a systematic review

OBJECTIVES

The use of magnetic resonance (MR) imaging in differentiation between benign and malignant adnexal masses in children and adolescents might be of great value in the diagnostic workup of sonographically indeterminate masses, since preserving fertility is of particular importance in this population. This systematic review evaluates the diagnostic value of MR imaging in children with an ovarian mass.

METHODS

The review was made according to the PRISMA Statement. PubMed and EMBASE were systematically searched for studies on the use of MR imaging in differential diagnosis of ovarian masses in both adult women and children from 2008 to 2018.

RESULTS

Sixteen paediatric and 18 adult studies were included. In the included studies, MR imaging has shown good diagnostic performance in differentiating between benign and malignant ovarian masses. MR imaging techniques including diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE) imaging seem to further improve the diagnostic performance.

CONCLUSION

The addition of DWI with apparent diffusion coefficient (ADC) values measured in enhancing components of solid lesions and DCE imaging may further increase the good diagnostic performance of MR imaging in the pre-operative differentiation between benign and malignant ovarian masses by increasing specificity. Prospective age-specific studies are needed to confirm the high diagnostic performance of MR imaging in children and adolescents with a sonographically indeterminate ovarian mass.

KEY POINTS

• MR imaging, based on several morphological features, is of good diagnostic performance in differentiating between benign and malignant ovarian masses. Sensitivity and specificity varied between 84.8 to 100% and 20.0 to 98.4%, respectively. • MR imaging techniques like diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE) imaging seem to improve the diagnostic performance. • Specific studies in children and adolescents with ovarian masses are required to confirm the suggested increased diagnostic performance of DWI and DCE in this population.

Ultrasonographic and multimodal imaging of pediatric genital female diseases

Ultrasonography is the first-line imaging modality in the evaluation of the female pelvis in childhood and adolescence, because it is easy to perform, non-invasive and it does not require sedation. The transabdominal approach is preferred in children and adolescents, after filling the bladder to move away the bowel loops from the pelvis. The probe frequency must be adapted to age, thickness of tissues and depth of the structures under examination. High-frequency (4-12 MHz) linear or convex probes are used in newborns; high-frequency linear probes (4-12 MHz) in toddler, convex 5-7.5 MHz probes in girls and convex 3.5-5 MHz probes in teenagers. In this article, the main pathological conditions of the genital female tract in pediatric age are examined, such as congenital anomalies, disorders of sex development, ovarian cysts, ovarian tumors, adnexal torsion, primary amenorrhea, precocious puberty and pelvic inflammatory disease.

Physiologic Ovarian Cysts versus Other Ovarian and Adnexal Pathologic Changes in the Preadolescent and Adolescent Population: US and Surgical Follow-up

Background Ovarian and adnexal cysts are frequently encountered at US examinations performed in preadolescent and adolescent patients, yet there are few published studies regarding the outcomes of cysts in this population. Purpose To identify characteristics at US that help to distinguish physiologic ovarian cysts from nonphysiologic entities. Materials and Methods Female patients who underwent pelvic US with or without Doppler from January 2009 through December 2013 were identified by using a centralized imaging database. Patients older than 7 years and younger than 18 years with ovarian or adnexal cysts at least 2.5 cm were included. Demographic characteristics, date of surgery, surgical notes, and pathologic reports were extracted from the electronic medical record. Initial and follow-up dates of US, cyst size and complexity, imaging diagnosis, and change on subsequent US images were recorded. Statistical analysis was performed with the Wilcoxon rank sum and Kruskal-Wallis tests for continuous variables and the Fisher exact test for categorical variables. Results Of 754 patients who met inclusion criteria (age, 8-18 years; mean age, 14.6 years ± 1.9 [standard deviation]; mean cyst size, 5 cm ± 3.3), 409 patients underwent complete follow-up that included resolution at imaging (n = 250) or surgery (n = 159). In the patients with complete imaging follow-up, mean time to US documentation of resolution was 194 days ± 321; 59.6% (149 of 250) patients had nonsimple cyst characteristics. One-hundred fifty-nine patients underwent surgical intervention (mean cyst size, 8.5 cm ± 5.3), and 69.8% (111 of 159) of the cysts had simple characteristics. Of the 159 cysts, 100 (62.8%) were defined in the pathologic report as paratubal cysts. Of 409 patients, no malignancies were encountered in this study population with surgical or imaging resolution. Conclusion No malignancies were encountered in the study population and the majority of cysts resolved at follow-up imaging. Large size, persistence, and separability from the ovary were most helpful for identification of nonphysiologic paratubal cysts. © RSNA, 2019.

Ovarian Teratoma or Uterine Malformation? PET/MRI as a Novel Useful Tool in NMDAR Encephalitis

This is a case report of a 17-year-old girl affected by N-methyl-D-aspartate-receptor (NMDAR) encephalitis suspected for a paraneoplastic syndrome. Ultrasound (US) and computed tomography (CT) imaging identified an ovarian lesion compatible with teratoma. ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/magnetic resonance imaging (PET/MRI), performed to evaluate metabolic activity of the brain and of the ovarian mass, correctly changed the diagnosis to uterine malformation that was later histologically proven.

Magnetic resonance imaging of pediatric adnexal masses and mimics

Evaluation of adnexal masses in children and adolescents relies on imaging for appropriate diagnosis and management. Pelvic MRI is indicated and adds value for all adnexal masses when surgery is considered or when ultrasound findings are indeterminate. Specifically, features on MR imaging can help distinguish between benign and malignant lesions, which not only influences the decision between surgery and conservative treatment, but also the type of surgery to be performed, including potential use of fertility-sparing approaches with minimally invasive techniques. Larger size, younger age, presentation with precocious puberty or virilization, restricted diffusion in a solid mass, and rapid and strong enhancement of solid components are all features concerning for malignancy. In addition, distinctive MR imaging features of adnexal masses, combined with clinical and laboratory biomarkers, might suggest a specific histological diagnosis.

Update on the surgical management of ovarian neoplasms in children and adolescents: analysis on 32 cases

This study analyzes updated clinical, diagnostic, and surgical directions for the treatment of ovarian neoplasms in children and adolescents, comparing them with a retrospective analysis of 32 cases treated in two Pediatric Surgery University Institutions. From January 2005 to December 2015, 32 pediatric patients were surgically treated for 32 ovarian tumors: 28 (87.5%) benign and 4 (12.5%) malignant neoplastic lesions. Median age at surgery was 11.2 years (12.8 years in patients with benign neoplasms, 7.25 years in patients with malignant ones). All patients with malignant and 25% of patients with benign ovarian lesions had elevated serum level of tumors markers. The surgical approach was laparotomic in 62.5% and laparoscopic in 37.5%; 81.2% surgeries were performed in elective surgery and 18.8% in emergency. Intraoperative frozen section analysis was performed in 18.75% of patients. The most frequent surgery (96.8%) was unilateral oophorectomy. After a median follow-up of 76 months (range 6-132 months), 31/32 patients are alive and disease-free. In case of malignant tumors, fertility-sparing surgery with accurate staging must be performed. Laparoscopic multiport is the gold standard approach for benign pediatric ovarian neoplasms, but the use of laparoscopy in full respect of oncological principles also for early stage malignant tumors is currently increased.

An Uncommon Case of Adolescent Ovarian Teratoma Incarcerated in Inguinal Hernia

Mature cystic teratoma is the most frequent benign ovarian neoplastic lesion in adolescents and is generally composed of fully differentiated tissue arising from multipotential three germinal layers. It accounts for approximately 50% of benign ovarian tumors in childhood. Rarely, a bilateral, synchronous, or metachronous presentation can be observed, supporting a conservative approach as the first surgical approach. We report a case of an ovarian mature cystic incarcerated in indirect inguinal hernia in a 15-year-old girl undergoing ovary-sparing surgery. To our knowledge this is the first case of such lesion incarcerated in an inguinal hernia reported in literature.

Diagnosis of Cystic Teratoma Facilitated by Point-of-Care Ultrasonography

Abdominal pain and constipation are common chief complaints in the pediatric emergency department. We present a case of a child with pain, abdominal distention, and constipation ultimately diagnosed with an ovarian teratoma and the role of point-of-care ultrasonography in the evaluation.

Ovarian lesion volumes as a screening tool for malignancy in adolescent ovarian tumors

BACKGROUND

Preoperative evaluation of ovarian tumors for malignancy is essential to determine appropriate treatment. Our study assessed the utility of ovarian lesion volumes to screen for malignancy in adolescent ovarian lesions.

METHODS

A retrospective chart review of adolescent patients (8-18years) who underwent an ovarian operation from January 2008 to December 2012. Data included demographics, ultrasonographic volume measurements, and tumor markers. Volumes were calculated using the prolate ellipsoid formula. Data are presented as medians.

RESULTS

One hundred twenty-three females were included at a median age of 13.7years (IQR 12.5-16). Eight patients had malignancies. The median benign lesion volume was significantly smaller than malignant [152cm3 (IQR 57-592)vs. 1548cm(3) (IQR 627-2105), p=0.001]. A receiver operating characteristic (ROC) curve analysis (AUC 0.84, p=0.001) revealed a threshold ovarian lesion volume of <184cm(3) (100% sensitivity, 54% specificity, NPV 100%, PPV 13%) to accurately screen for malignancy. This held true when applied to our dataset as none of the 62 girls with volumes <184cm(3) had malignant pathology.

CONCLUSIONS

This is the first documented use of ovarian lesion volumes as a screening tool in adolescent ovarian lesions. This should be used in conjunction with tumor markers and other imaging features to better screen for malignancy.

Treatment of ovarian lesions in children and adolescents: a retrospective study of 130 cases

In this study, we analyze the management of ovarian masses in a total of 130 children surgically treated for 137 ovarian lesions (7 bilateral). The most frequent symptoms were chronic (52.3%) and acute (25.4%) abdominal pain. Histological examination revealed 64 (46.7%) functional lesions, 59 (43.1%) benign neoplasms, 5 (3.7%) malignant ones, and 7 (6.6%) torsed normal ovaries. Ovarian torsion occurred in 36 cases (26.27%). A conservative treatment was performed in 81 (59.1%) girls: 61 (75.3%) treated in nonemergency and 20 (24.7%) in emergency surgery; laparoscopic approach in 35 cases (43.2%); and open surgery in 46 (56.8%). The remaining 56 (40.9%) ovarian masses underwent nonconservative surgery: 40 cases (71.4%) nonemergency and 16 (28.6%) emergency; laparoscopy in 20 patients (35.7%); and open surgery in 36 (64.3%). Fertility preservation should be a goal in the surgical treatment. The management of ovarian torsion should include adnexal detorsion and recovery of the ovarian tissue. In case of benign neoplasms, laparoscopic tumorectomy should be the gold standard; in early stage malignant tumors, fertility-sparing surgery with accurate staging is preferred.

Ovarian tumors in children and adolescents: a series of 41 cases

OBJECTIVE

Pictorial review with a detailed semiological analysis of ovarian tumors in children and adolescents to provide a relevant diagnostic approach.

PATIENTS AND METHODS

Retrospective study (2001-2011) of 41 patients under the age of 15 who underwent surgery for an ovarian mass with a definite pathological diagnosis.

RESULTS

Sixty-two percent of the lesions were benign, 33% were malignant and 5% were borderline. Germ cell tumors were most frequent (77.5%), followed by sex cord stromal tumors (12.5%) and epithelial tumors (7.5%). Malignant tumors were more frequent in children between 0 and 2 years old. On imaging, calcifications and fat were specific for germ cell tumors; the presence of a mural nodule was predictive of a mature teratoma (P<0.001). Predictive factors for malignancy were clinical, including abdominal distension (P<0.01) or a palpable mass (P=0.05), biological, including increased hCG and/or AFP levels (P<0.001) and radiological, including tumors larger than 12 cm (P<0.05), tumoral hypervascularity (P<0.01) and voluminous ascites (P<0.01).

CONCLUSION

This semiological analysis confirms the role of imaging in diagnosing the etiology of ovarian lesions in children and adolescents and emphasizes the importance identifying tumoral hypervascularity, which, in addition to classic criteria, is highly predictive of malignancy.

Magnetic resonance imaging of pediatric pelvic masses

Both benign and malignant pelvic masses are encountered in the pediatric population. Although ultrasonography remains the modality of choice for initial evaluation of a pediatric pelvic mass, in selected cases magnetic resonance (MR) imaging can add important diagnostic information. MR imaging has several advantages over ultrasonography and computed tomography, including superior contrast resolution and an ability to characterize abnormalities based on unique tissue characteristics. MR evaluation assists in lesion characterization, presurgical planning, and staging when a malignancy is suspected. MR imaging also offers a nonionizing imaging modality for long-term follow-up of patients undergoing therapy for malignant pelvic masses.

Ovarian masses in children and adolescents - an analysis of 521 clinical cases

OBJECTIVE

To analyze the clinical characteristics of ovarian masses in children and adolescents.

MATERIALS AND METHODS

We performed a retrospective analysis of patients less than 20 years of age who were treated at the Obstetrics and Gynecology Hospital of Fudan University between March 2003 and January 2012. Medical records were reviewed for age at operation, including presentation of symptoms and signs; the levels of tumor markers; imaging examinations; pathologic findings; the size of masses; treatment; and outcome. Data management and descriptive analyses were performed using SPSS 16.0.

RESULTS

A total of 521 patients were included in this study. Among them, 92 had non-neoplastic lesions, 382 had benign neoplasms, and 47 had malignant tumors. The mean age of the patients was 16.3 ± 2.2 years. The primary presenting symptoms and signs were abdominal pain (39.5%), menstrual disorder (31.1%), abdominal swelling (5.4%), and an enlarged abdominal perimeter (3.3%). Malignant tumors tended to be larger than benign neoplasms (17.3 ± 8.6 cm vs 9.0 ± 5.7 cm; P = .000). There was no age difference between patients with benign neoplasms (16.3 ± 2.1 y) and those with malignant tumors (15.7 ± 2.5 y). The operations included salpingo-oophorectomy, ovarian cystectomy, and oophorectomy. Two patients with malignant tumors had bilateral salpingo-oophorectomy, and 2 patients who had tumor metastasis underwent a total abdominal hysterectomy and bilateral salpingo-oophorectomy. Forty-one cases of malignant tumors received postoperative chemotherapy.

CONCLUSIONS

Germ cell tumors are the most common malignancy, and mature teratomas are the most common benign neoplasms in children and adolescents. Abdominal pain and menstrual disorder are the main reasons for doctor's visit. Although examination by ultrasound is the preferred auxiliary in the diagnosis of ovarian pathology, it could not distinguish between benign and malignant tumors. However, tumor size and tumor markers are helpful to identify the properties of masses. Surgery is usually better for treatment, and it is preferable to attempt conservative, fertility-sparing surgery in adolescents. Postoperative chemotherapy is necessary for malignant tumors.

US of the pediatric female pelvis

This review presents the normal and pathologic development of the gonads and genitourinary tract and addresses the role of ultrasonography in the diagnosis and management of gynecologic disorders of the pediatric pelvis, including ambiguous genitalia, prepubertal bleeding, primary amenorrhea, pelvic mass, and pelvic pain.

Overexpression of cysteine cathepsin L is a marker of invasion and metastasis in ovarian cancer

Cysteine cathepsins (CTSs) are involved in the degradation and remodeling of the extracellular matrix and are associated with cellular transformation, differentiation, motility and adhesion in cancer development. Previous studies indicate that CTSs may be involved in ovarian cancer invasion and metastasis. However, due to the lack of large sample clinical studies and direct experimental evidence for the relationship between the expression of CTSs and invasion and metastasis, the diagnostic and prognostic value of CTSs in ovarian cancer progression has not been elucidated. In the present study, we observed that expression levels of CTSB, CTSL and CC in malignant ovarian tumors were significantly higher than the expression levels in benign tumors and normal ovarian tissues, yet their associations with clinicopathological features varied. In particular, CTSL was related to lymph node metastasis, CC was related to liver metastasis and omental metastasis, and CTSB and CTSL expression levels were found to be independent prognostic factors in ovarian cancer. Further study indicated that the serum level of CTSL was significantly higher in patients with ovarian malignant tumors than the levels in benign tumors and healthy controls, and the levels were elevated in low grade and advanced stage compared to the levels in high grade and early stage disease, suggesting that the serum level of CTSL may be a useful serum marker for the diagnosis of ovarian cancer. Furthermore, the expression of CTSL in ovarian cancer cells can greatly enhance the ability of cell invasion and metastasis, although no change was observed for cell adhesion. Taken together, we demonstrated that the overexpression of CTSL is involved in tumor invasion and metastasis, and the CTSL level in serum may be a marker for invasion and metastasis in ovarian cancer.

DNA methylation analysis reveals distinct methylation signatures in pediatric germ cell tumors

Background

Aberrant DNA methylation is a prominent feature of many cancers, and may be especially relevant in germ cell tumors (GCTs) due to the extensive epigenetic reprogramming that occurs in the germ line during normal development.

Methods

We used the Illumina GoldenGate Cancer Methylation Panel to compare DNA methylation in the three main histologic subtypes of pediatric GCTs (germinoma, teratoma and yolk sac tumor (YST); N = 51) and used recursively partitioned mixture models (RPMM) to test associations between methylation pattern and tumor and demographic characteristics. We identified genes and pathways that were differentially methylated using generalized linear models and Ingenuity Pathway Analysis. We also measured global DNA methylation at LINE1 elements and evaluated methylation at selected imprinted loci using pyrosequencing.

Results

Methylation patterns differed by tumor histology, with 18/19 YSTs forming a distinct methylation class. Four pathways showed significant enrichment for YSTs, including a human embryonic stem cell pluripotency pathway. We identified 190 CpG loci with significant methylation differences in mature and immature teratomas (q < 0.05), including a number of CpGs in stem cell and pluripotency-related pathways. Both YST and germinoma showed significantly lower methylation at LINE1 elements compared with normal adjacent tissue while there was no difference between teratoma (mature and immature) and normal tissue. DNA methylation at imprinted loci differed significantly by tumor histology and location.

Conclusion

Understanding methylation patterns may identify the developmental stage at which the GCT arose and the at-risk period when environmental exposures could be most harmful. Further, identification of relevant genetic pathways could lead to the development of new targets for therapy.