Fluorescence In Situ Hybridization (FISH) Detection of Chromosomal 12p Anomalies in Testicular Germ Cell Tumors

Gonadal Teratomas: A State-of-the-Art Review in Pathology

Teratomas are neoplasms arising from germ cells and encompass tissues derived from two or more embryonic germ layers, including ectoderm, mesoderm, and endoderm. These tumours typically localize along the midline or in paramedian positions and can manifest as gonadal (20%) or extragonadal (80%) entities. Although gonadal teratomas are uncommon, they represent the predominant type of gonadal tumour in the paediatric population. They comprise approximately 20-25% of all ovarian tumours in females and about 3-5% of all testicular tumours in males. Ovarian teratomas exhibit a higher incidence in early childhood and adolescence, whereas testicular teratomas are more prevalent during the first three months of life and between the ages of 15 and 19. While the majority of paediatric gonadal teratomas are benign, malignant or mixed variants may also arise, necessitating more aggressive therapeutic interventions.

Somatic mutation detection and KRAS amplification in testicular germ cell tumors

BACKGROUND

Testicular Germ Cell Tumors (TGCT) are the most common cancer among young adult men. The TGCT histopathology is diverse, and the frequency of genomic alterations, along with their prognostic role, remains largely unexplored. Herein, we evaluate the mutation profile of a 15-driver gene panel and copy number variation of KRAS in a large series of TGCT from a single reference cancer center.

MATERIALS AND METHODS

A cohort of 97 patients with TGCT, diagnosed at the Barretos Cancer Hospital, was evaluated. Real-time PCR was used to assess copy number variation (CNV) of the KRAS gene in 51 cases, and the mutation analysis was performed using the TruSight Tumor 15 (Illumina) panel (TST15) in 65 patients. Univariate analysis was used to compare sample categories in relation to mutational frequencies. Survival analysis was conducted by the Kaplan-Meier method and log-rank test.

RESULTS

KRAS copy number gain was a very frequent event (80.4%) in TGCT and presented a worse prognosis compared with the group with no KRAS copy gain (10y-OS, 90% vs. 81.5%, p = 0.048). Among the 65 TGCT cases, different variants were identified in 11 of 15 genes of the panel, and the TP53 gene was the most recurrently mutated driver gene (27.7%). Variants were also detected in genes such as KIT, KRAS, PDGFRA, EGFR, BRAF, RET, NRAS, PIK3CA, MET, and ERBB2, with some of them potentially targetable.

CONCLUSION

Although larger studies incorporating collaborative networks may shed the light on the molecular landscape of TGCT, our findings unveal the potential of actionable variants in clinical management for applying targeted therapies.

Fluorescent in-situ hybridization test performed on cell blocks is useful for establishing germ cell origin of metastatic tumors with unusual clinical presentation

The majority of germ cell tumors (GCTs) are characterized by iso-chromosome 12p (i12p) abnormality. The aim of this study is to review the cytomorphologic features and analyze the utility of i12p fluorescent in-situ hybridization (FISH) test in diagnosing metastatic GCTs primarily evaluated by cytologic techniques in patients without prior history of GCTs. The laboratory information system was queried over a period of 10 years to search for cases where i12p FISH test was requested on cytology material. FISH test was performed using TelVysion 12p telomeric probe and CEP 12 centromere probe on cell-blocks. A ratio of 12ptel/CEP12 signal of 1.4 or greater was considered as positive. Patient demographics, clinical presentation, cytopathologic findings, and follow-up surgical resection data were reviewed and correlated. A total of three cases were identified, all men (age range 31-60 years). Cytologic diagnoses were favor metastatic embryonal carcinoma (Case 1, retroperitoneal fluid FNA), metastatic yolk sac tumor/YST (Case 2, lung mass FNA) and adenocarcinoma, likely representing a somatic-type malignancy (SM) arising from a preexisting GCT (Case 3, retroperitoneal mass FNA). This limited study demonstrated high sensitivity for detecting i12p abnormality by FISH test performed on cell blocks. The cytomorphology of extra-gonadal GCTs varies according to the histologic subtype. Sarcomatoid morphology of YST, SM or mixed GCTs further complicates cytology evaluation. FISH test for detection of i12p performed on cell-blocks is extremely useful in establishing germ cell origin of these metastatic GTCs with unusual cytomorphology and guides management in patients without prior history of GCTs.

Multitarget fluorescence in situ hybridization diagnostic applications in solid and hematological tumors

Introduction: Multitarget FISH (mFISH) is a technique allowing for simultaneous detection of multiple targets sequences on the same slide through the choice of spectrally distinct fluorophore labels. The mFISH could represent a useful tool in the field of precision oncology.Areas covered: This review discusses the potential applications of mFISH technology in the molecular diagnosis of different solid and hematological tumors, including non-small cell lung cancers, melanomas, renal cell carcinomas, bladder carcinomas, germ cell tumors, and multiple myeloma, as commonly required in the clinical practice.Expert Opinion: In this emerging era of the tailored therapies and newer histo-molecular classifications, there are increasing numbers of predictive and diagnostic biomarkers required for effective clinical care. The mFISH approach may have several applications in the common clinical practice, improving the molecular diagnosis in terms of time, cost and preservation of biomaterial for tumors with a limited amount of tumor available. The mFISH provides several advantages compared to other high-throughput technologies; however, it requires high level of expertise required to interpret complex results.