Challenging interpretation of germline TP53 variants based on the experience of a national comprehensive cancer centre.

TP53 variant interpretation is still challenging, especially in patients with attenuated Li-Fraumeni syndrome (LFS). We investigated the prevalence of pathogenic/likely pathogenic (P/LP) variants and LFS disease in the Hungarian population of cancer patients. By testing 893 patients with multiplex or familial cancer, we identified and functionally characterized novel splice variants of TP53 helping accurate variant classification. The differences among various semi-automated interpretation platforms without manual curation highlight the importance of focused interpretation as the automatic classification systems do not apply the TP53-specific criteria. The predicted frequency of the TP53 P/LP variants in Hungary is 0.3 per million which most likely underestimates the real prevalence. The higher detection rate of disease-causing variants in patients with attenuated LFS phenotype compared to the control population (OR 12.5; p < 0.0001) may raise the potential benefit of the TP53 genetic testing as part of the hereditary cancer panels of patients with multiple or familial cancer even when they do not meet Chompret criteria. Tumours developed at an earlier age in phenotypic LFS patients compared to the attenuated LFS patients which complicates genetic counselling as currently there are no different recommendations in surveillance protocols for LFS, phenotypic LFS, and attenuated LFS patients.

Osteosarcoma of the Mandible in a Patient with Florid Cemento-Osseous Dysplasia and Li-Fraumeni Syndrome: A Rare Coincidence.

Cemento-osseous dysplasia (COD) is the most common benign fibro-osseous lesion of the jaws and generally considered non-neoplastic and self-limited. Here, we present a 30-year old female who noticed a bilateral swelling of her posterior mandible with irregular periapical mineralization and incomplete root resorption on panoramic radiographs. A biopsy revealed florid COD and no further treatment was initiated. 9 years later, she presented with a progressive expansion of her left posterior mandible after being treated for bilateral breast cancer 4 and 8 years before. CT scans showed expansile and densely mineralized lesions in all four quadrants with the left posterior mandible showing a focal penetration of the buccal cortical bone. Biopsies revealed an osteoblastic high-grade osteosarcoma in the left and a COD in the right mandible, notably with cellular atypia in the spindle cell component. The patient underwent segmental resection of the left mandible with clear margins and adjuvant chemotherapy. Subsequent genetic testing identified a heterozygous germline TP53 mutation (p.V173G) which confirmed the clinically suspected Li-Fraumeni syndrome (LFS). 3 years after the resection, the patient is free of disease and the other foci of COD remained stable in size on follow-up imaging analyses. Our case illustrates LFS-related osteosarcoma developing within florid COD. Given the rarity of this coincidence, a causative relation between the two lesions seems unlikely but in patients with tumor predisposition syndromes it might be advisable to closely monitor even benign lesions like COD.

Prevalence of Cancer at Baseline Screening in the National Cancer Institute Li-Fraumeni Syndrome Cohort.

Importance: Establishment of an optimal cancer surveillance program is important to reduce cancer-related morbidity and mortality in individuals with Li-Fraumeni syndrome, a rare, highly penetrant cancer predisposition syndrome. Objective: To determine the feasibility and efficacy of a comprehensive cancer screening regimen in Li-Fraumeni syndrome, using multiple radiologic techniques, including rapid whole-body magnetic resonance imaging (MRI) and laboratory measurements. Design, Setting, and Participants: Baseline evaluation of a prospective cancer screening study was conducted from June 1, 2012, to July 30, 2016, at the National Cancer Institute, National Institutes of Health (an academic research facility). Participants included 116 individuals with Li-Fraumeni syndrome with a germline TP53 pathogenic variant who were aged 3 years or older at the time of baseline screening and had not received active cancer therapy at least 6 months prior to screening. Main Outcomes and Measures: Detection of prevalent cancer with multimodal screening techniques and the need for additional evaluation. Results: Of the 116 study participants, 77 (66.4%) were female; median age was 37.6 years (range, 3-68 years). Baseline cancer screening led to the diagnosis of cancer in 8 (6.9%) individuals (2 lung adenocarcinomas, 1 osteosarcoma, 1 sarcoma, 1 astrocytoma, 1 low-grade glioma, and 2 preinvasive breast cancers [ductal carcinoma in situ]); all but 1 required only resection for definitive treatment. A total of 40 (34.5%) participants required additional studies to further investigate abnormalities identified on screening, with 32 having incidental, benign, or normal findings, resulting in a false-positive rate of 29.6%. Non-MRI techniques, including baseline blood tests, abdominal ultrasonography in children, mammography, and colonoscopy, did not lead to a diagnosis of prevalent cancer in our cohort. Conclusions and Relevance: This study describes the establishment and feasibility of an intensive cancer surveillance protocol for individuals with Li-Fraumeni syndrome. Prevalent cancers were detected at an early stage with baseline whole-body, brain, and breast MRI. Prospective screening of the participants is under way.

Androgen production in pediatric adrenocortical tumors may occur via both the classic and/or the alternative backdoor pathway.

Children with adrenocortical tumors (ACTs) often present with virilization due to high tumoral androgen production, with dihydrotestosterone (DHT) as most potent androgen. Recent work revealed two pathways for DHT biosynthesis, the classic and the backdoor pathway. Usage of alternate routes for DHT production has been reported in castration-resistant prostate cancer, CAH and PCOS. To assess whether the backdoor pathway may contribute to the virilization of pediatric ACTs, we investigated seven children suffering from androgen producing tumors using steroid profiling and immunohistochemical expression studies. All cases produced large amounts of androgens of the classic and/or backdoor pathway. Variable expression of steroid enzymes was observed in carcinomas and adenomas. We found no discriminative pattern. This suggests that enhanced androgen production in pediatric ACTs is the result of deregulated steroidogenesis through multiple steroid pathways. Thus future treatments of ACTs targeting androgen overproduction should consider these novel steroid production pathways.

Avaliação do impacto do suporte familiar e da espiritualidade no aconselhamento genético de portadores da Síndrome de Li-Fraumeni e Li-Fraumeni Like / Evaluation of the impact of family support and spirituality in genetic counseling of patients with Li-Fraumeni and Li-Fraumeni Like Syndromes

O Glioblastoma (GBM) é o tumor de células gliais mais comum e agressivo dentre os tumores cerebrais primários. Caracterizar mecanismos moleculares associados com a progressão desse tumor pode auxiliar no desenvolvimento de novas estratégias para seu tratamento e garantir a maior sobrevida de pacientes. A proteína STAT3 (Proteína transdutora de sinal e ativadora de transcrição 3) é um fator de transcrição ativado por fosforilação e conhecido por seu importante papel na gliomagênese. Com o uso de microarranjos de tecidos (TMAs) avaliamos a expressão total e a localização nuclear de STAT3 e de suas formas fosforiladas pSTAT3 (Y705) e pSTAT3(S727) em astrocitomas e tecido cerebral não tumoral. STAT3 possui uma localização nuclear aumentada em GBMs humanos, quando comparada com astrocitomas de menor grau ou tecido cerebral não tumoral. Interessantemente, o aumento da localização nuclear de STAT3 nos GBMs não está associado com o incremento de suas formas fosforiladas. Além disso, altos níveis de STAT3 nuclear em GBM estão correlacionados com o menor tempo livre de recidiva e a uma menor sobrevida nesses pacientes. Esse perfil não foi visto para as formas fosforiladas, indicando que outros mecanismos de ativação de STAT3, que não a via canônica de fosforilação, podem estar presentes nos GBMs. A identificação dessas modificações pode representar uma nova estratégia terapêutica para a abordagem desses tumores uma vez que as drogas disponíveis atualmente têm como alvo os domínios fosforilados de STAT3. Uma modificação pós-traducional que poderia contribuir para a translocação nuclear de STAT3 é a SUMOilação. A proteína PIAS1 (Proteína inibidora da atividade de STAT1) está envolvida neste mecanismo por mediar a adição de SUMO (Pequena proteína modificadora relacionada à ubiquitina) às proteínas-alvo. Nossos dados mostraram que PIAS1 apresenta maior localização nuclear em GBM quando comparado ao tecido não tumoral. Além disso, PIAS1 promove o acúmulo nuclear...

Glioblastoma is the most common and aggressive primary brain tumor. This work was conducted to characterize molecular mechanisms associated with GBM progression that could assist in developing of new strategies for its treatment and ensure better overall survival of these patients. STAT3 (Signal Transducer and Activator of Transcription 3) is a transcription factor activated by phosphorylation and known for its important role in gliomagenesis. Using tissue microarrays (TMAs) we evaluated the total expression and nuclear localization of STAT3 and its phosphorylated forms, pSTAT3 (Y705) and pSTAT3 (S727) in astrocytomas and non-tumor brain tissue. GBMs showed higher levels of nuclear STAT3 compared to lower grade astrocitomas or non-tumor brain tissue. Interestingly, increased nuclear STAT3 in GBMs is not associated with the improvement of its phosphorylated forms. Moreover, high levels of nuclear STAT3 in GBMs correlate with lower free-recurrence survival and overall survival of these patients. This profile followed by its phosphorylated forms, indicating that other activation mechanisms besides than the canonical STAT3 phosphorylation is present in GBM. The identification of these post-translation modifications may represent new therapeutic strategies for the treatment of these tumors since the currently available drugs target only the phosphorylation sites of STAT3. A posttranslational modification that could contribute to nuclear translocation of STAT3 is the SUMOylation although we were unable to see this interaction in cultured cells. On the other hand, GBMs have a higher nuclear PIAS1 compared to non-tumor brain tissue. PIAS1 protein (Protein Inhibitor of Activity of STAT1) is involved in protein SUMOylation by mediating the addition of SUMO to target proteins. Moreover, PIAS1 promotes nuclear retention of the co-chaperone STI1/Hop (Stress inducible protein 1/Hsp70- Hsp90 organizing protein) in astrocytes treated with gamma radiation, which may...

[Li-Fraumeni syndrome: clinico-molecular diagnostics and medico-genetic counseling].

Li-Fraumeni syndrome (sarcoma family syndrome, OMIM 151623) is a rare clinically and genetically hetergoeneous autosomal dominant disorder characterized by the evolvement and accumulation of soft-tissue osteogenic sarcomas in members of a family, as well as uni- and bilateral breast cancer in young women, brain tumours, adrenocortical cancer, and lymphoproliferative diseases. Germinal mutations of the TP53 gene constitute the etiological genetic basis of Li-Fraumeni syndrome. American Society of Clinical Oncology (ASCO) and National Comprehensive Cancer Network developed recommendations for genetic testing and observation of carriers of TP53 mutations. In vitro and in vivo studies demonstrated correlation between the TP53-mutant genotype and resistance to standard therapeutic modalities. This finding gave impetus to the development of new genotherapeutic approaches to the treatment of TP53-associated tumours in patients with Li-Fraumeni syndrome.

Effects of chemopreventive and antitelomerase agents on the spontaneous immortalization of breast epithelial cells.

BACKGROUND: Activation of telomerase is an early event in the development of breast and other cancers that may lead to cell immortalization, a critical and rate-limiting step in cancer progression. Breast epithelial cells from women with Li-Fraumeni syndrome (LFS) immortalize spontaneously and reproducibly in culture. We, therefore, tested whether immortalization of these cells could be prevented by treating them with chemopreventive agents and by inhibiting telomerase activity. METHODS: Noncancerous, preimmortal breast epithelial cells derived from a patient with LFS were treated for 3 months with nontoxic concentrations of the chemopreventive agents oltipraz, difluoromethylornithine, tamoxifen, and retinoic acid or with two different telomerase inhibitors. The frequency of spontaneous immortalization of LFS-derived cells was estimated by an approach based on fluctuation analyses. Statistical analyses were two-sided. RESULTS: The frequency of spontaneous immortalization events of LFS-derived breast epithelial cells was reduced by long-term treatment with retinoic acid (P<0.001) or tamoxifen (P<0.05) compared with solvent-treated cells. The frequency of immortalization was also reduced by treating LFS-derived cells with an antitelomerase antisense oligonucleotide (P<0.001) or by inducing the cells to express a dominant negative mutant of telomerase (P<0.025) compared with cells treated with a control oligonucleotide or with empty vector, respectively. CONCLUSIONS: Treatment of preimmortal LFS breast epithelial cells with chemopreventive and antitelomerase agents decreased the frequency of spontaneous immortalization in vitro. These studies validate the application of a new cell culture model system to screen the effects of novel chemopreventive agents by use of cell immortalization as an end point. The results also suggest that the telomerase ribonucleoprotein complex may be an important molecular target for breast cancer prevention.