Teratoma-associated and so-called pure Wilms tumour of the ovary represent two separate tumour types with distinct molecular features.

AIMS: Ovarian Wilms tumour (WT)/nephroblastoma is an extremely rare neoplasm that has been reported to occur in pure form or as a component of a teratomatous neoplasm. We hypothesized that teratoma-associated and pure ovarian WT may represent different tumour types with diverging molecular backgrounds. To test this hypothesis, we comprehensively characterized a series of five tumours originally diagnosed as ovarian WT. METHODS AND RESULTS: The five cases comprised three teratoma-associated (two mature and one immature) and two pure WTs. Two of the teratoma-associated WTs consisted of small nodular arrangements of "glandular"/epithelial structures, while the third consisted of both an epithelial and a diffuse spindle cell/blastemal component. The pure WTs consisted of "glandular" structures, which were positive for sex cord markers (including inhibin and SF1) together with a rhabdomyosarcomatous component. The two pure WTs harboured DICER1 pathogenic variants (PVs), while the three associated with teratomas were DICER1 wildtype. Panel-based DNA sequencing of four of the cases did not identify PVs in the other genes investigated. Analysis of the HA19/IGF2 imprinting region showed retention of imprinting in the pure WTs but loss of heterozygosity with hypomethylation of the ICR1 region in two of three teratoma-associated WTs. Furthermore, copy number variation and clustering-based whole-genome DNA methylation analyses identified divergent molecular profiles for pure and teratoma-associated WTs. CONCLUSION: Based on the morphological features, immunophenotype, and molecular findings (DICER1 PVs, copy number, and DNA methylation profiles), we suggest that the two cases diagnosed as pure primary ovarian WT represent moderately to poorly differentiated Sertoli Leydig cell tumours (SLCTs), while the tumours arising in teratomas represent true WTs. It is possible that at least some prior cases reported as pure primary ovarian WT represent SLCTs.

Mesenchymal Hamartoma of the Liver and DICER1 Syndrome.

Mesenchymal hamartoma of the liver (MHL) is a benign tumor affecting children that is characterized by a primitive myxoid stroma with cystically dilated bile ducts. Alterations involving chromosome 19q13 are a recurrent underlying cause of MHL; these alterations activate the chromosome 19 microRNA cluster (C19MC). Other cases remain unexplained. We describe two children with MHLs that harbored germline DICER1 pathogenic variants. Analysis of tumor tissue from one of the children revealed two DICER1 "hits." Mutations in DICER1 dysregulate microRNAs, mimicking the effect of the activation of C19MC. Our data suggest that MHL is a new phenotype of DICER1 syndrome. (Funded by the Canadian Institutes of Health Research and others.).

DICER1-associated embryonal rhabdomyosarcoma and adenosarcoma of the gynecologic tract: Pathology, molecular genetics, and indications for molecular testing.

Gynecologic sarcomas are uncommon neoplasms, the majority occurring in the uterus. Due to the diverse nature of these, the description of "new" morphological types and the rarity of some of them, pathological diagnosis and treatment is often challenging. Finding genetic alterations specific to, and frequently occurring, in a certain type can aid in the diagnosis. DICER1 is a highly conserved ribonuclease crucial in the biogenesis of microRNAs and mutations in DICER1 (either somatic or germline) have been detected in a wide range of sarcomas including genitourinary embryonal rhabdomyosarcomas (ERMS) and adenosarcomas. Importantly, DICER1-associated sarcomas share morphological features irrespective of the site of origin such that the pathologist can strongly suspect a DICER1 association. A review of the literature shows that almost all gynecologic ERMS reported (outside of the vagina) harbor DICER1 alterations, while approximately 20% of adenosarcomas also do so. These two tumor types exhibit significant morphological overlap and DICER1 tumor testing may be helpful in distinguishing between them, because a negative result makes ERMS unlikely. Given that germline pathogenic DICER1 variants are frequent in uterine (corpus and cervix) ERMS and pathogenic germline variants in this gene cause a hereditary cancer predisposition syndrome (DICER1 syndrome), patients diagnosed with these neoplasms should be referred to medical genetic services. Cooperation between pathologists and geneticists is crucial and will help in improving the diagnosis and management of these uncommon sarcomas.

The Value of DICER1 Mutation Analysis in "Subtle" Diagnostically Challenging Embryonal Rhabdomyosarcomas of the Uterine Cervix.

Embryonal rhabdomyosarcoma of the uterine cervix is a rare neoplasm which is almost invariably associated with pathogenic somatic or germline DICER1 mutations; patients with germline mutations have DICER1 syndrome. We report 2 subtle cervical embryonal rhabdomyosarcoma, one occurring in a 21-yr-old woman with a known history of DICER1 syndrome and the other in a 19-yr-old woman with no history of DICER1 syndrome or DICER1-associated neoplasms. Both neoplasms focally involved otherwise benign endocervical polyps and were characterized histologically by subtle areas of increased stromal cellularity, nuclear atypia and mitotic activity; there was focal nuclear staining of these areas with the skeletal muscle markers myogenin and myoD1. In both cases, demonstration of a somatic DICER1 RNase IIIb mutation in the tumor was instrumental in establishing the diagnosis. We believe these neoplasms represent the earliest discernible phase of cervical embryonal rhabdomyosarcoma. Pathologists should have a high index of suspicion when atypical stromal elements are present in endocervical polyps and immunohistochemistry together with DICER1 sequencing will assist in diagnosis.

Significantly greater prevalence of DICER1 alterations in uterine embryonal rhabdomyosarcoma compared to adenosarcoma.

Embryonal rhabdomyosarcomas (ERMS) account for 2-3% of cancers in pediatric and adolescent populations. They are rarer in adults. We and others have reported that ERMS arising in the uterine cervix may harbor mutations in the gene encoding the microRNA biogenesis enzyme, DICER1, but a large series of cases has not been published. In the uterus, distinguishing ERMS from adenosarcoma can be very challenging, even for expert pathologists, and DICER1 alterations have been identified in a variable subset of uterine adenosarcomas. We hypothesized that DICER1 genetic testing may be useful in distinguishing between ERMS and adenosarcoma. We conducted a central pathology review-based study of 64 tumors initially thought to be uterine ERMS or adenosarcoma; 19 neoplasms had a consensus diagnosis of ERMS, 27 of adenosarcoma and for 18, no consensus diagnosis was reached. The median age at diagnosis was 30 years (range 2.5-69) for ERMS, 57.5 years (range 27-82) for adenosarcoma, and 65.5 years (range 32-86) for no consensus cases. In our series, the DICER1 mutation prevalence differed between the three groups: DICER1 alterations were present in 18/19 (95%) ERMS, 7/27 (26%) adenosarcomas (p < 0.001), and 4/18 (22%) no consensus cases. A germline alteration was present in 6/12 ERMS patients tested versus 0/6 adenosarcoma patients. Thus, although DICER1 mutations are near ubiquitous in uterine ERMS and are significantly less common in uterine adenosarcoma, DICER1 testing is only of value in distinguishing between the two neoplasms when a DICER1 mutation is absent, as this is helpful in excluding ERMS. On review of the clinical and radiological features of the single DICER1 wild-type cervical ERMS, this was thought most likely to be of vaginal origin. Given the significant prevalence of DICER1 germline pathogenic variants in uterine ERMS, all patients with this diagnosis should be referred to a genetics service.

Genes and variants in hematopoiesis-related pathways are associated with gemcitabine/carboplatin-induced thrombocytopenia.

Chemotherapy-induced myelosuppression, including thrombocytopenia, is a recurrent problem during cancer treatments that may require dose alterations or cessations that could affect the antitumor effect of the treatment. To identify genetic markers associated with treatment-induced thrombocytopenia, we whole-exome sequenced 215 non-small cell lung cancer patients homogeneously treated with gemcitabine/carboplatin. The decrease in platelets (defined as nadir/baseline) was used to assess treatment-induced thrombocytopenia. Association between germline genetic variants and thrombocytopenia was analyzed at single-nucleotide variant (SNV) (based on the optimal false discovery rate, the severity of predicted consequence, and effect), gene, and pathway levels. These analyses identified 130 SNVs/INDELs and 25 genes associated with thrombocytopenia (P-value < 0.002). Twenty-three SNVs were validated in an independent genome-wide association study (GWAS). The top associations include rs34491125 in JMJD1C (P-value = 9.07 × 10-5), the validated variants rs10491684 in DOCK8 (P-value = 1.95 × 10-4), rs6118 in SERPINA5 (P-value = 5.83 × 10-4), and rs5877 in SERPINC1 (P-value = 1.07 × 10-3), and the genes CAPZA2 (P-value = 4.03 × 10-4) and SERPINC1 (P-value = 1.55 × 10-3). The SNVs in the top-scoring pathway "Factors involved in megakaryocyte development and platelet production" (P-value = 3.34 × 10-4) were used to construct weighted genetic risk score (wGRS) and logistic regression models that predict thrombocytopenia. The wGRS predict which patients are at high or low toxicity risk levels, for CTCAE (odds ratio (OR) = 22.35, P-value = 1.55 × 10-8), and decrease (OR = 66.82, P-value = 5.92 × 10-9). The logistic regression models predict CTCAE grades 3-4 (receiver operator characteristics (ROC) area under the curve (AUC) = 0.79), and large decrease (ROC AUC = 0.86). We identified and validated genetic variations within hematopoiesis-related pathways that provide a solid foundation for future studies using genetic markers for predicting chemotherapy-induced thrombocytopenia and personalizing treatments.

A Pilot, Phase II, Randomized, Open-Label Clinical Trial Comparing the Neurotoxicity of Three Dose Regimens of Nab-Paclitaxel to That of Solvent-Based Paclitaxel as the First-Line Treatment for Patients with Human Epidermal Growth Factor Receptor Type 2-Negative Metastatic Breast Cancer.

BACKGROUND: This study aimed to characterize the neurotoxicity of three different regimens of nab-paclitaxel compared with a standard regimen of solvent-based (sb) paclitaxel for the first-line treatment of HER2-negative metastatic breast cancer based on the Total Neurotoxicity Score (TNS), a tool specifically developed to assess chemotherapy-induced neurotoxicity. MATERIALS AND METHODS: This was a randomized, open-label study testing 4-week cycles of 80 mg/m2 sb-paclitaxel (PACL80/w) on days 1, 8, and 15; 100 mg/m2 nab-paclitaxel on days 1, 8, and 15 (NAB100/w); 150 mg/m2 nab-paclitaxel on days 1, 8, and 15 (NAB150/w); and 150 mg/m2 nab-paclitaxel on days 1 and 15 (NAB150/2w). In addition to the TNS, neuropathy was assessed using the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE). Tumor response and quality of life were also evaluated. RESULTS: Neurotoxicity, as evaluated by the TNS, did not significantly differ between the sb-paclitaxel group and any of the nab-paclitaxel groups. The frequency of (any grade) polyneuropathy, as measured by the NCI-CTCAE, was lower in the PACL80/w (n = 7, 50%) and NAB150/2w (n = 10, 62.5%) groups than in the NAB100/w (n = 13, 81.3%) or NAB150/w (n = 11, 78.6%) group. Although the differences were not statistically significant, compared with the other groups, in the NAB150/w group, the time to occurrence of grade ≥2 polyneuropathy was shorter, and the median time to recovery from grade ≥2 polyneuropathy was longer. Dose delays and reductions due to neurotoxicity and impact of neurotoxicity on the patients' experience of symptoms and functional limitations was greater with NAB150/w. Among the seven polymorphisms selected for genotyping, the variant alleles of EPHA5-rs7349683, EPHA6-rs301927, and EPHA8-rs209709 were associated with an increased risk of paclitaxel-induced neuropathy. CONCLUSION: The results of this exploratory study showed that, regardless of the dose, nab-paclitaxel did not differ from sb-paclitaxel in terms of neurotoxicity as evaluated with the TNS. However, results from NCI-CTCAE, dose delays and reductions, and functional tools consistently indicate that NAB150/w regimen is associated with a greater risk of chemotherapy-induced neuropathy. Thus, our results question the superiority of the TNS over NCI-CTCAE for evaluating chemotherapy-induced neuropathy and guiding treatment decisions in this context. The selection of the nab-paclitaxel regimen should be individualized based on the clinical context and potentially supported by pharmacogenetic analysis. Registry: EudraCT, 2012-002361-36; NCT01763710 IMPLICATIONS FOR PRACTICE: The results of this study call into question the superiority of the Total Neurotoxicity Score over the National Cancer Institute Common Terminology Criteria for Adverse Events for evaluating chemotherapy-induced neuropathy and guiding treatment decisions in this context and suggest that a regimen of 150 mg/m2 nab-paclitaxel administered on days 1, 8, and 15 is associated with a greater risk of chemotherapy-induced neuropathy and hematological toxicity compared with other lower-dose nab-paclitaxel regimens or a standard regimen of solvent-based paclitaxel. The selection of the nab-paclitaxel regimen should be individualized based on the clinical context and could benefit from pharmacogenetics analysis.

Concomitant Medications and Risk of Chemotherapy-Induced Peripheral Neuropathy.

BACKGROUND: Peripheral neuropathy is the dose-limiting toxicity of many oncology drugs, including paclitaxel. There is large interindividual variability in the neuropathy, and several risk factors have been proposed; however, many have not been replicated. Here we present a comprehensive study aimed at identifying treatment and physiopathology-related paclitaxel-induced neuropathy risk factors in a large cohort of well-characterized patients. PATIENTS AND METHODS: Analyses included 503 patients with breast or ovarian cancer who received paclitaxel treatment. Paclitaxel dose modifications caused by the neuropathy were extracted from medical records and patients self-reported neuropathy symptoms were collected. Multivariate logistic regression analyses were performed to identify concomitant medications and comorbidities associated with paclitaxel-induced neuropathy. RESULTS: Older patients had higher neuropathy: for each increase of 1 year of age, the risk of dose modifications and grade 3 neuropathy increased 4% and 5%, respectively. Cardiovascular drugs increased the risk of paclitaxel dose reductions (odds ratio [OR], 2.51; p = .006), with a stronger association for beta-adrenergic antagonists. The total number of concomitant medications also showed an association with dose modifications (OR, 1.25; p = .012 for each concomitant drug increase). A dose modification predictive model that included the new identified factors gave an area under the curve of 0.74 (p = 1.07 × 10-10). Preexisting nerve compression syndromes seemed to increase neuropathy risk. CONCLUSION: Baseline characteristics of the patients, including age and concomitant medications, could be used to identify individuals at high risk of neuropathy, personalizing chemotherapy treatment and reducing the risk of severe neuropathy. IMPLICATIONS FOR PRACTICE: Peripheral neuropathy is a common adverse effect of many cancer drugs, including chemotherapeutics, targeted therapies, and immune checkpoint inhibitors. About 40% of survivors of cancer have functional deficits caused by this toxicity, some of them irreversible. Currently, there are no effective treatments to prevent or treat this neuropathy. This study, performed in a large cohort of well-characterized patients homogenously treated with paclitaxel, identified concomitant medications, comorbidities, and demographic factors associated with peripheral neuropathy. These factors could serve to identify patients at high risk of severe neuropathy for whom alternative non-neurotoxic alternatives may be considered.

Influence of donor liver CYP3A4*20 loss-of-function genotype on tacrolimus pharmacokinetics in transplanted patients.

OBJECTIVE: Cytochrome P450 3A4 (CYP3A4) metabolizes about half of all drugs on the market; however, the impact of CYP3A4 loss-of-function variants on drug exposures remains poorly characterized. Here, we report the effect of the CYP3A4*20 frameshift allele in two Spanish liver transplant patients treated with tacrolimus. PATIENTS AND METHODS: A series of 90 transplanted patients (with DNA available for 89 of the recipients and 76 of the liver donors) treated with tacrolimus were included in the study. The genotypes of liver donors and of the recipients for CYP3A4*20 (rs67666821), CYP3A4*22 (rs35599367) and CYP3A5*3 (rs776746) were compared with weight-adjusted tacrolimus dose (D), tacrolimus trough concentration (C0), and dose-adjusted tacrolimus trough concentrations (C0/D) using the Mann-Whitney U-nonparametric test. RESULTS: The CYP3A4*20 allele was detected in two of the liver donors. This genotype yielded at all times higher C0/D (2.6-fold, average) than intermediate CYP3A metabolizers (CYP3A4*1/*1 and CYP3A5*3/*3) (P=0.045, 90 days after transplantation). CYP3A4*22 carriers showed a 1.9-fold average increase in C0/D (P=0.047, 0.025, and 0.053; at days 7, 14, and 30 after transplantation, respectively) compared with intermediate metabolizers. In terms of recipients' genotype, CYP3A5*1 had reduced (P=0.025) and CYP3A4*22 increased C0/D (P=0.056) 7 days after transplantation. The incidence of biopsy-proven acute rejection was 0, 12, and 20% for livers with poor, intermediate, and extensive CYP3A-metabolizing capacity, respectively (P=0.0995). CONCLUSION: This first description of CYP3A4*20 null genotype in liver-transplanted patients, supports the relevance of CYP3A genotyping in tacrolimus therapy.

Advanced sporadic renal epithelioid angiomyolipoma: case report of an extraordinary response to sirolimus linked to TSC2 mutation.

BACKGROUND: Renal epithelioid angiomyolipomas (EAML) are rare tumors with aggressive behavior. EAML can be sporadic or develop within the tuberous sclerosis complex syndrome, where mutations of TSC1 or TSC2 genes (critical negative regulators of mTOR Complex 1) result in an increased activation of mTOR pathway. Optimal EAML treatment, including mTOR inhibitors, remains undetermined. CASE PRESENTATION: Here we present the case of a young adult with a renal EAML that after radical nephrectomy developed metastases, first in liver and then in lumbar vertebrae. After complete surgical resection of these lesions, liver recurrence was detected, this time with incomplete surgical resection. After finding a new liver lesion, systemic treatment with sirolimus started. The patient exhibited a complete and durable response to this drug, being disease free at the time of publication, after 36 months of treatment. Targeted next generation sequencing (NGS) of MTOR, TSC1 and TSC2 genes in the primary tumor, metastasis and blood of the patient, revealed one inactivating TSC2 mutation (c.2739dup; p.K914*) in the tumor cells. Immunohistochemistry revealed decreased TSC2 protein content and increased phospho-S6 in the tumor cells, demonstrating mTOR pathway activation. CONCLUSION: NGS on an EAML patient with an extraordinary response to sirolimus uncovered TSC2 inactivation as the mechanism for the response. This study supports NGS as a useful tool to identify patients sensitive to mTOR inhibitors and supports the treatment of malignant EAML with these drugs.

Biallelic TSC2 Mutations in a Patient With Chromophobe Renal Cell Carcinoma Showing Extraordinary Response to Temsirolimus.

mTOR inhibitors are used to treat renal cell carcinoma (RCC). Treatment response is variable and appears to correlate with genetic alterations that activate mTOR signaling. Recently, everolimus was suggested to be more effective than sunitinib in chromophobe RCC (chRCC), a tumor with frequent mTOR pathway defects. This report presents the genomic and functional characterization of a metastatic chRCC that showed complete response at metastatic sites and 80% reduction in primary tumor size upon temsirolimus treatment. After surgery, the patient remained disease-free for 8 years after temsirolimus therapy. Whole-exome sequencing (WES) revealed 2 somatic variants in TSC2, a critical negative regulator of mTOR: a splicing defect (c.5069-1G>C) and a novel missense variant [c.3200_3201delinsAA; p.(V1067E)]. In vitro functional assessment demonstrated that the V1067E substitution disrupted TSC2 function. Immunohistochemistry in the tumor tissues revealed increased phosphorylated S6 ribosomal protein, indicating mTOR pathway activation. In conclusion, WES revealed TSC2 inactivation as the likely mechanism for this extraordinary response to temsirolimus. These findings support high efficacy of mTOR inhibitors in a subset of patients with chRCC and propose sequencing of mTOR pathway genes to help guide therapy.

A case of neuroblastoma in DICER1 syndrome: Chance finding or noncanonical causation?

DICER1 syndrome is an inherited disorder associated with at least a dozen rare, mainly pediatric-onset tumors. Its characterization remains incomplete. Some studies suggested that neuroblastoma (NB) may be involved in this syndrome. Here, we describe the case of a 14-year-old female presenting with a multinodular goiter (MNG) and a collision tumor composed of NB and cystic nephroma (CN). She is a carrier of a deleterious germline mutation in exon 23 of DICER1 and harbored different somatic mutations in the CN and MNG. However, no second hit was found in the NB, questioning its status as a DICER1-related tumor.

Evaluation of KDR rs34231037 as a predictor of sunitinib efficacy in patients with metastatic renal cell carcinoma.

The identification of biomarkers able to predict clinical benefit from vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors is urgently needed. Recently, Maitland and colleagues described an association between KDR-rs34231037 and soluble VEGFR2 levels as well as pazopanib pharmacodynamics. We investigated in a well-characterized series of metastatic clear cell renal cell carcinoma patients whether rs34231037 could influence sunitinib response. Clinical data and DNA were available from an international series of 276 patients. KDR-rs34231037 association with sunitinib response, clinical benefit, and progression-free survival was analyzed using logistic and Cox regression analyses. We found that G-allele carriers were over-represented among patients with clinical benefit during sunitinib treatment compared with those refractory to the treatment (odds ratio: 3.78; 95% confidence interval: 1.02-14.06; P=0.047, multivariable analysis). In conclusion, rs34231037 variant carriers seemed to have better sunitinib response than wild-type patients. Moreover, the association with tumor size reduction suggests that this single nucleotide polymorphism might also identify patients with successful tumor downsizing under anti-VEGFR therapy.

Genetic polymorphisms of SCN9A are associated with oxaliplatin-induced neuropathy.

BACKGROUND: Oxaliplatin is a chemotherapy agent active against digestive tumors. Peripheral neuropathy is one of the most important dose-limiting toxicity of this drug. It occurs in around 60-80% of the patients, and 15% of them develop severe neuropathy. The pathophysiology of oxaliplatin neurotoxicity remains unclear. SCN9A is a gene codifying for a subtype sodium channel (type IX, subunit α) and mutations in this gene are involved in neuropathic perception. In this study we investigated whether SCN9A genetic variants were associated with risk of neurotoxicity in patients diagnosed of cancer on treatment with oxaliplatin. METHODS: Blood samples from 94 patients diagnosed of digestive cancer that had received oxaliplatin in adjuvant or metastatic setting were obtained from three hospitals in Madrid. These patients were classified into two groups: "cases" developed oxaliplatin-induced grade 3-4 neuropathy (n = 48), and "controls" (n = 46) had no neuropathy or grade 1. The neuropathy was evaluated by an expert neurologist and included a clinical examination and classification according to validated neurological scales: National Cancer Institute Common Toxicity Criteria (NCI-CTC), Oxaliplatin-Specific Neurotoxicity Scale (OSNS) and Total Neuropathy score (TNS). Genotyping was performed for 3 SCN9A missense polymorphisms: rs6746030 (R1150W), rs74401238 (R1110Q) and rs41268673 (P610T), and associations between genotypes and neuropathy were evaluated. RESULTS: We found that SCN9A rs6746030 was associated with protection for severe neuropathy (OR = 0.39, 95% CI = 0.16-0.96; p = 0.041). Multivariate analysis adjusting for diabetes provided similar results (p = 0.036). No significant differences in neuropathy risk were detected for rs74401238 and rs41268673. CONCLUSION: SCN9A rs6746030 was associated with protection for severe oxaliplatin-induced peripheral neuropathy. The validation of this exploratory study is ongoing in an independent series.

Exceptional Response to Temsirolimus in a Metastatic Clear Cell Renal Cell Carcinoma With an Early Novel MTOR-Activating Mutation.

mTOR pathway inhibitors are important drugs for the treatment of advanced renal cell carcinoma (RCC). However, no valid predictive markers have been identified to guide treatment selection and identify patients who are sensitive to these drugs. Mutations activating the mTOR pathway have been suggested to predict response; however, their predictive value is still unclear. Here, we present the genomic and functional characterization of a patient with metastatic clear cell RCC (ccRCC) who experienced a partial response to temsirolimus after a poor response to 2 previous lines of treatment. At the time of publication, the patient was disease-free 8 years after temsirolimus treatment. Multiregion whole-exome sequencing (WES) on 3 regions of the primary tumor, 1 metastasis, and blood revealed tumor mutations in driver genes in ccRCC: a missense mutation in VHL (p.W88L), a loss-of-function mutation in BAP1 (p.E454Rfs*15), and a novel missense mutation in MTOR (p.Y1974H). The MTOR mutation was present in all tumor regions, with similar allele frequency as the VHL mutation, and in vitro functional assessment of the MTOR variant demonstrated that it increased mTORC1 activity. Consistently, immunohistochemistry in the tumor samples demonstrated increased levels of phospho-S6. In conclusion, multiregion WES identified a novel MTOR mutation acquired early during tumor development as the event leading to a high sensitivity to temsirolimus treatment. This study supports tumor multiregion sequencing to detect truncal mutations in the mTOR pathway to identify patients sensitive to mTOR inhibitors.

Recommendations for somatic and germline genetic testing of single pheochromocytoma and paraganglioma based on findings from a series of 329 patients.

BACKGROUND: Nowadays, 65-80% of pheochromocytoma and paraganglioma (PPGL) cases are explained by germline or somatic mutations in one of 22 genes. Several genetic testing algorithms have been proposed, but they usually exclude sporadic-PPGLs (S-PPGLs) and none include somatic testing. We aimed to genetically characterise S-PPGL cases and propose an evidence-based algorithm for genetic testing, prioritising DNA source. METHODS: The study included 329 probands fitting three criteria: single PPGL, no syndromic and no PPGL family history. Germline DNA was tested for point mutations in RET and for both point mutation and gross deletions in VHL, the SDH genes, TMEM127, MAX and FH. 99 tumours from patients negative for germline screening were available and tested for RET, VHL, HRAS, EPAS1, MAX and SDHB. RESULTS: Germline mutations were found in 46 (14.0%) patients, being more prevalent in paragangliomas (PGLs) (28.7%) than in pheochromocytomas (PCCs) (4.5%) (p=6.62×10(-10)). Somatic mutations were found in 43% of those tested, being more prevalent in PCCs (48.5%) than in PGLs (32.3%) (p=0.13). A quarter of S-PPGLs had a somatic mutation, regardless of age at presentation. Head and neck PGLs (HN-PGLs) and thoracic-PGLs (T-PGLs) more commonly had germline mutations (p=2.0×10(-4) and p=0.027, respectively). Five of the 29 metastatic cases harboured a somatic mutation, one in HRAS. CONCLUSIONS: We recommend prioritising testing for germline mutations in patients with HN-PGLs and T-PGLs, and for somatic mutations in those with PCC. Biochemical secretion and SDHB-immunohistochemistry should guide genetic screening in abdominal-PGLs. Paediatric and metastatic cases should not be excluded from somatic screening.

Impact of chemotherapy on telomere length in sporadic and familial breast cancer patients.

Recently, we observed that telomeres of BRCA1/2 mutation carriers were shorter than those of controls or sporadic breast cancer patients, suggesting that mutations in these genes might be responsible for this event. Given the contradictory results reported in the literature, we tested whether other parameters, such as chemotherapy, could be modifying telomere length (TL). We performed a cross-sectional study measuring leukocyte TL of 266 sporadic breasts cancer patients treated with first-line chemotherapy, with a median follow-up of 240 days. Additionally, we performed both cross-sectional and longitudinal studies in a series of 236 familial breast cancer patients that included affected and non-affected BRCA1/2 mutation carriers. We have measured in leukocytes from peripheral blood: the TL, percentage of short telomeres (<3 kb), telomerase activity levels and the annual telomere shortening speed. In sporadic cases we found that chemotherapy exerts a transient telomere shortening effect (around 2 years) that varies depending on the drug combination. In familial cases, only patients receiving treatment were associated with telomere shortening but they recovered normal TL after a period of 2 years. Chemotherapy affects TL and should be considered in the studies that correlate TL with disease susceptibility.

Estrogen Receptor Expression in DICER1-related Lesions is Associated With the Presence of Cystic Components.

DICER1 tumor predisposition syndrome results from pathogenic variants in DICER1 and is associated with a variety of benign and malignant lesions, typically involving kidney, lung, and female reproductive system. Over 70% of sarcomas in DICER1 tumor predisposition syndrome occur in females. Notably, pediatric cystic nephroma (pCN), a classic DICER1 tumor predisposition syndrome lesion, shows estrogen receptor (ER) expression in stromal cells. There are also renal, hepatic, and pancreatic lesions unassociated with DICER1 tumor predisposition syndrome that have an adult female predominance and are characterized/defined by ER-positive stromal cells. Except for pCN, the expression of ER in DICER1-associated lesions remains uninvestigated. In the present study, ER expression was assessed by immunohistochemistry in 89 cases of DICER1-related lesions and 44 lesions lacking DICER1 pathogenic variants. Expression was seen in stromal cells in pCN and pleuropulmonary blastoma (PPB) types I and Ir, whereas anaplastic sarcoma of kidney and PPB types II and III were typically negative, as were other solid tumors of non-Müllerian origin. ER expression was unrelated to the sex or age of the patient. Expression of ER showed an inverse relationship to preferentially expressed antigen in melanoma (PRAME) expression; as lesions progressed from cystic to solid (pCN/anaplastic sarcoma of kidney, and PPB types I to III), ER expression was lost and (PRAME) expression increased. Thus, in DICER1 tumor predisposition syndrome, there is no evidence that non-Müllerian tumors are hormonally driven and antiestrogen therapy is not predicted to be beneficial. Lesions not associated with DICER1 pathogenic variants also showed ER-positive stromal cells, including cystic pulmonary airway malformations, cystic renal dysplasia, and simple renal cysts in adult kidneys. ER expression in stromal cells is not a feature of DICER1 perturbation but rather is related to the presence of cystic components.