ABSTRACT
BACKGROUND: Testicular germ cell tumors (TGCT) are unique malignancies of young adult men; their biology is, however, underexplored and there has not been much progress in their treatment for decades. Circulating free tumor DNA (cfDNA) analysis represents a promising way of discovering novel diagnostic and treatment options. OBJECTIVE: The study evaluates the clinical value of cfDNA detection in TGCT patients. DESIGN AND METHODS: Total cfDNA concentration and ratio of its 2 main fragments (180 and 360 bp) were evaluated by spectrophotometry, capillary electrophoresis and qPCR in peripheral blood plasma of 96 TGCT patients (173 samples) and 31 normal controls. Non-parametric tests were used for statistical analyses. RESULTS: The total cfDNA concentration was significantly higher in TGCT than in controls (P < 0.0001), with the highest levels at disease progression, but with no clear threshold between malignant and normal samples. Patients with positive tumor markers had higher cfDNA concentrations than those with negative markers (Pâ¯=â¯0.01). Longer 360 bp cfDNA fragments were found in 58% of TGCT patients including almost all samples from relapse or disease progression but no normal controls (P < 0.0001). CONCLUSION: Total cfDNA levels are significantly increased in TGCT patients but without a clear threshold separating normal and tumor samples, thus total cfDNA amount itself is not a sensitive enough marker to identify or monitor TGCT. Longer cfDNA fragments have been found exclusively in a proportion of tumors and predominantly at disease progression, representing a novel potential marker for TGCT monitoring that would deserve further exploration.
Subject(s)
Cell-Free Nucleic Acids , Circulating Tumor DNA , Neoplasms, Germ Cell and Embryonal , Testicular Neoplasms , Biomarkers, Tumor , Disease Progression , Humans , Male , Young AdultABSTRACT
The emergence of cisplatin (CDDP) resistance is the main cause of treatment failure and death in patients with testicular germ cell tumors (TGCT), but its biologic background is poorly understood. To study the molecular basis of CDDP resistance in TGCT we prepared and sequenced CDDP-exposed TGCT cell lines as well as 31 primary patients' samples. Long-term exposure to CDDP increased the CDDP resistance 10 times in the NCCIT cell line, while no major resistance was achieved in Tera-2. Development of CDDP resistance was accompanied by changes in the cell cycle (increase in G1 and decrease in S-fraction), increased number of acquired mutations, of which 3 were present within ATRX gene, as well as changes in gene expression pattern. Copy number variation analysis showed, apart from obligatory gain of 12p, several other large-scale gains (chr 1, 17, 20, 21) and losses (chr X), with additional more CNVs found in CDDP-resistant cells (e.g., further losses on chr 1, 4, 18, and gain on chr 8). In the patients' samples, those who developed CDDP resistance and died of TGCT (2/31) showed high numbers of acquired aberrations, both SNPs and CNVs, and harbored mutations in genes potentially relevant to TGCT development (e.g., TRERF1, TFAP2C in one patient, MAP2K1 and NSD1 in another one). Among all primary tumor samples, the most commonly mutated gene was NSD1, affected in 9/31 patients. This gene encoding histone methyl transferase was also downregulated and identified among the 50 most differentially expressed genes in CDDP-resistant NCCIT cell line. Interestingly, 2/31 TGCT patients harbored mutations in the ATRX gene encoding a chromatin modifier that has been shown to have a critical function in sexual differentiation. Our research newly highlights its probable involvement also in testicular tumors. Both findings support the emerging role of altered epigenetic gene regulation in TGCT and CDDP resistance development.
ABSTRACT
Approximately 15% of men with newly diagnosed cancer are younger than 55 years, and about 26% of them are younger than 20 years. However the most common cause of fertility disorders is oncological treatment itself, the oncological diseases, changes in anatomy, and primary or secondary hormonal insufficiency are also significant factors. The chemotherapy, radiation, or their combination reduce sperm count, impair sperm motility and cause disorders in morphology and DNA integrity. Prognosis of sperm production recovery depends on the type of cancer, stage of the disease, patient age, drug treatment, treatment route and dosage, and pre-treatment male fertility.
