The Li-Fraumeni syndrome

A dual biomarker in non-small cell lung cancer that predicts Li Fraumeni syndrome : Lung cancer and Li Fraumeni

Non-small cell lung cancer is the most common cause of cancer death globally. When apparent incidental pathogenic germline variants (PGVs) are uncovered with routine next generation sequencing (NGS) of NSCLCs, germline testing (GT) is recommended to confirm that PGV. Because it is far more common that an uncovered tumor TP53 variant is related to a somatic event than an incidental PGV, however, GT for Li Fraumeni syndrome (LFS) is not recommended based solely on uncovering a NSCLC TP53 variant. Because nearly all tumor EGFR variants are also somatic in origin, GT is not recommended based solely on uncovering a tumor EGFR variant.However, there is evidence that patients with coexisting NSCLC variants in both EGFR and TP53 have significant likelihoods of having LFS. For patients with LFS, there are recommended measures for prevention and early detection of LFS-associated cancers and cascade GT of relatives for LFS. Although co-existing genetic variants in NSCLC are not currently used as a biomarker for GT to identify patients with PGVs, given the evidence reviewed here, select patients with NSCLCs that harbor this dual biomarker (i.e., co-existing TP53/EGFR variants) might reasonably be considered for GT for LFS.

Overview of familial syndromes with increased skin malignancies

The vast majority of skin cancers can be classified into two main types: melanoma and keratinocyte carcinomas. The most common keratinocyte carcinomas include basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Multiple familial syndromes have been identified that can increase the risk of developing SCC, BCC, and/or melanoma. The major syndromes include oculocutaneous albinism for SCC, basal cell nevus syndrome for BCC, familial atypical multiple mole-melanoma syndrome, and hereditary breast and ovarian cancer syndrome for melanoma. In addition, familial syndromes that can predispose individuals to all three major skin cancers include xeroderma pigmentosum and Li-Fraumeni syndrome. This review highlights the epidemiology, risk factors, pathogenesis, and etiology of the major and minor syndromes to better identify and manage these conditions. Current investigational trials in genomic medicine are making their way in revolutionizing the clinical diagnosis of these familial syndromes for earlier preventative measures and improvement of long-term prognosis in these patients.

Genetic/Familial High-Risk Assessment: Breast, Ovarian, and Pancreatic, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

The NCCN Guidelines for Genetic/Familial High-Risk Assessment: Breast, Ovarian, and Pancreatic focus primarily on assessment of pathogenic or likely pathogenic variants associated with increased risk of breast, ovarian, and pancreatic cancer and recommended approaches to genetic testing/counseling and management strategies in individuals with these pathogenic or likely pathogenic variants. This manuscript focuses on cancer risk and risk management for BRCA-related breast/ovarian cancer syndrome and Li-Fraumeni syndrome. Carriers of a BRCA1/2 pathogenic or likely pathogenic variant have an excessive risk for both breast and ovarian cancer that warrants consideration of more intensive screening and preventive strategies. There is also evidence that risks of prostate cancer and pancreatic cancer are elevated in these carriers. Li-Fraumeni syndrome is a highly penetrant cancer syndrome associated with a high lifetime risk for cancer, including soft tissue sarcomas, osteosarcomas, premenopausal breast cancer, colon cancer, gastric cancer, adrenocortical carcinoma, and brain tumors.

Nationwide germline whole genome sequencing of 198 consecutive pediatric cancer patients reveals a high incidence of cancer prone syndromes

PURPOSE

Historically, cancer predisposition syndromes (CPSs) were rarely established for children with cancer. This nationwide, population-based study investigated how frequently children with cancer had or were likely to have a CPS.

METHODS

Children (0-17 years) in Denmark with newly diagnosed cancer were invited to participate in whole-genome sequencing of germline DNA. Suspicion of CPS was assessed according to Jongmans'/McGill Interactive Pediatric OncoGenetic Guidelines (MIPOGG) criteria and familial cancer diagnoses were verified using population-based registries.

RESULTS

198 of 235 (84.3%) eligible patients participated, of whom 94/198 (47.5%) carried pathogenic variants (PVs) in a CPS gene or had clinical features indicating CPS. Twenty-nine of 198 (14.6%) patients harbored a CPS, of whom 21/198 (10.6%) harbored a childhood-onset and 9/198 (4.5%) an adult-onset CPS. In addition, 23/198 (11.6%) patients carried a PV associated with biallelic CPS. Seven of the 54 (12.9%) patients carried two or more variants in different CPS genes. Seventy of 198 (35.4%) patients fulfilled the Jongmans' and/or MIPOGG criteria indicating an underlying CPS, including two of the 9 (22.2%) patients with an adult-onset CPS versus 18 of the 21 (85.7%) patients with a childhood-onset CPS (p = 0.0022), eight of the additional 23 (34.8%) patients with a heterozygous PV associated with biallelic CPS, and 42 patients without PVs. Children with a central nervous system (CNS) tumor had family members with CNS tumors more frequently than patients with other cancers (11/44, p = 0.04), but 42 of 44 (95.5%) cases did not have a PV in a CPS gene.

CONCLUSION

These results demonstrate the value of systematically screening pediatric cancer patients for CPSs and indicate that a higher proportion of childhood cancers may be linked to predisposing germline variants than previously supposed.

Identification of hereditary cancer in the general population: development and validation of a screening questionnaire for obtaining the family history of cancer

One of the challenges for Latin American countries is to include in their healthcare systems technologies that can be applied to hereditary cancer detection and management. The aim of the study is to create and validate a questionnaire to identify individuals with possible risk for hereditary cancer predisposition syndromes (HCPS), using different strategies in a Cancer Prevention Service in Brazil. The primary screening questionnaire (PSQ) was developed to identify families at‐risk for HCPS. The PSQ was validated using discrimination measures, and the reproducibility was estimated through kappa coefficient. Patients with at least one affirmative answer had the pedigree drawn using three alternative interview approaches: in‐person, by telephone, or letter. Validation of these approaches was done. Kappa and intraclass correlation coefficients were used to analyze data's reproducibility considering the presence of clinical criteria for HCPS. The PSQ was applied to a convenience sample of 20,000 women of which 3121 (15.6%) answered at least one affirmative question and 1938 had their pedigrees drawn. The PSQ showed sensitivity and specificity scores of 94.4% and 75%, respectively, and a kappa of 0.64. The strategies for pedigree drawing had reproducibility coefficients of 0.976 and 0.850 for the telephone and letter approaches, respectively. Pedigree analysis allowed us to identify 465 individuals (24.0%) fulfilling at least one clinical criterion for HCPS. The PSQ fulfills its function, allowing the identification of HCPS at‐risk families. The use of alternative screening methods may reduce the number of excluded at‐risk individuals/families who live in locations where oncogenetic services are not established.

Familial Gastric Cancers

Although the majority of gastric carcinomas are sporadic, approximately 10% show familial aggregation, and a hereditary cause is determined in 1%-3% cases. Of these, hereditary diffuse gastric cancer is the most recognized predisposition syndrome. Although rare, the less commonly known syndromes also confer a markedly increased risk for development of gastric cancer. Identification and characterization of these syndromes require a multidisciplinary effort involving oncologists, surgeons, genetic counselors, biologists, and pathologists. This article reviews the molecular genetics, clinical and pathologic features, surveillance guidelines, and preventive measures of common and less common hereditary gastric cancer predisposition syndromes.

Easing the Burden: Describing the Role of Social, Emotional and Spiritual Support in Research Families with Li-Fraumeni Syndrome

This study presents findings of a mixed-method descriptive exploration of the role of friends and spirituality/religiosity in easing the burden of families with the rare inherited disorder, Li-Fraumeni Syndrome (LFS). LFS is caused by germline mutations in the TP53 gene and is associated with very high lifetime risk of developing one or more malignancies. During the first clinical visit we assessed several types of social support among a subset of study participants (N = 66) using an established interactive research tool called the Colored Eco-Genetic Relationship Map (CEGRM). We performed both quantitative and qualitative analyses of social relationships with LFS family members and close non-kin. Distress scores (N = 59) were mostly low normal, with some outliers. We found that reported friendships varied widely, that the friendships were often deep and enduring, and were important sources of informational, tangible, emotional and spiritual support. Confidantes tended to be best friends and/or spouses. Organized religion was important in selected families, typically from mainstream traditions. However, a number of people identified themselves as "spiritual" and reported spiritual and humanist explorations. Our results shed preliminary light on how some people in families with LFS cope in the face of tremendous medical, social and emotional challenges.

Age at cancer onset in germline TP53 mutation carriers: association with polymorphisms in predicted G-quadruplex structures

Germline TP53 mutations predispose to multiple cancers defining Li-Fraumeni/Li-Fraumeni-like syndrome (LFS/LFL), a disease with large individual disparities in cancer profiles and age of onset. G-quadruplexes (G4s) are secondary structural motifs occurring in guanine tracks, with regulatory effects on DNA and RNA. We analyzed 85 polymorphisms within or near five predicted G4s in TP53 in search of modifiers of penetrance of LFS/LFL in Brazilian cancer families with (n = 35) or without (n = 110) TP53 mutations. Statistical analyses stratified on family structure showed that cancer tended to occur ~15 years later in mutation carriers who also carried the variant alleles of two polymorphisms within predicted G4-forming regions, rs17878362 (TP53 PIN3, 16 bp duplication in intron 3; P = 0.082) and rs17880560 (6 bp duplication in 3' flanking region; P = 0.067). Haplotype analysis showed that this inverse association was driven by the polymorphic status of the remaining wild-type (WT) haplotype in mutation carriers: in carriers with a WT haplotype containing at least one variant allele of rs17878362 or rs17880560, cancer occurred ~15 years later than in carriers with other WT haplotypes (P = 0.019). No effect on age of cancer onset was observed in subjects without a TP53 mutation. The G4 in intron 3 has been shown to regulate alternative p53 messenger RNA splicing, whereas the biological roles of predicted G4s in the 3' flanking region remain to be elucidated. In conclusion, this study demonstrates that G4 polymorphisms in haplotypes of the WT TP53 allele have an impact on LFS/LFL penetrance in germline TP53 mutation carriers.

Gastric tumours in hereditary cancer syndromes: clinical features, molecular biology and strategies for prevention

Gastric cancer is the major cause of cancer-related deaths worldwide. The majority of them are classified as sporadic, whereas the remaining 10% exhibit familial clustering. Hereditary diffuse gastric cancer (HDGC) syndrome is the most important condition that leads to hereditary gastric cancer. However, other hereditary cancer syndromes, such as hereditary non-polyposis colorectal cancer, familial adenomatous polyposis, Peutz-Jeghers syndrome, Li-Fraumeni syndrome and hereditary breast and ovarian cancer, entail a higher risk compared to the general population for developing this kind of neoplasia. In this review, we describe briefly the most important aspects related to clinical features, molecular biology and strategies for prevention in hereditary gastric associated to different cancer syndromes.

Familial gastric cancer: update for practice management

About 90% of gastric carcinoma presents a sporadic setting and only 10% shows a familial cluster; among this group, 1-3% are considered as hereditary syndromes, with a clear genetic pathway. The most important genetic mechanisms are associated with CDH1 germline mutations, causing the hereditary diffuse gastric cancer syndrome. Other inherited predispositions with gastric carcinoma are the hereditary nonpolyposis colorectal cancer, Li-Fraumeni and Peutz-Jeghers syndromes. In this brief update, we described these principal hereditary syndromes offering a simple management to physicians where are these diseases diagnosed.

Exploiting the nucleotide substrate specificity of repair DNA polymerases to develop novel anticancer agents

The genome is constantly exposed to mutations that can originate during replication or as a result of the action of both endogenous and/or exogenous damaging agents [such as reactive oxygen species (ROS), UV light, genotoxic environmental compounds, etc.]. Cells have developed a set of specialized mechanisms to counteract this mutational burden. Many cancer cells have defects in one or more DNA repair pathways, hence they rely on a narrower set of specialized DNA repair mechanisms than normal cells. Inhibiting one of these pathways in the context of an already DNA repair-deficient genetic background, will be more toxic to cancer cells than to normal cells, a concept recently exploited in cancer chemotherapy by the synthetic lethality approach. Essential to all DNA repair pathways are the DNA pols. Thus, these enzymes are being regarded as attractive targets for the development of specific inhibitors of DNA repair in cancer cells. In this review we examine the current state-of-the-art in the development of nucleotide analogs as inhibitors of repair DNA polymerases.

Association of the germline TP53 R72P and MDM2 SNP309 variants with breast cancer survival in specific breast tumor subgroups

The tumor suppressor gene TP53 and its regulator MDM2 are both important players in the DNA-damage repair "TP53 response pathway". Common germline polymorphisms in these genes may affect outcome in patients with tumors characterized by additional somatic changes in the same or a related pathway. To evaluate this hypothesis, we determined the effect of the common germline TP53 R72P and MDM2 SNP309 polymorphisms on breast cancer survival in a consecutive cohort of breast cancer patients (age at diagnosis <53 years, n = 295) with gene expression data available. Patients were classified in subgroups according to their tumor TP53 mutation status and three gene expression profiles; a TP53 mutation status expression signature, a PTEN/PI3K pathway signature and the 70-gene prognosis profile. Survival analyses were performed using Cox regression models adjusting for clinico-pathological characteristics and treatment. An increase in breast cancer-specific mortality was observed for carriers of the germline MDM2 SNP309 rare GG-genotype (range hazard ratios: 2-3) or TP53 R72P heterozygous GC-genotype (range hazard ratios: 1-2) compared to those having the common genotypes within subgroups of tumors displaying a "more aggressive phenotype" gene expression profile. There was no evidence of such an effect on survival within the TP53-mutated tumor group for TP53 R72P carriers but a suggestion of an effect for MDM2 SNP309 carriers (GG vs. TT-genotype HR 2.99, P = 0.06). These results indicate that common polymorphisms in specific pathways may add to the worse prognosis of patients with tumors in which these pathways are affected by somatic alterations.

A molecular signature of normal breast epithelial and stromal cells from Li-Fraumeni syndrome mutation carriers

Specific changes in gene expression during cancer initiation should enable discovery of biomarkers for risk assessment, early detection and targets for chemoprevention. It has been previously demonstrated that altered mRNA and proteome signatures of morphologically normal cells bearing a single inherited "hit" in a tumor suppressor gene parallel many changes observed in the corresponding sporadic cancer. Here, we report on the global gene expression profile of morphologically normal, cultured primary breast epithelial and stromal cells from Li-Fraumeni syndrome (LFS) TP53 mutation carriers. Our analyses identified multiple changes in gene expression in both morphologically normal breast epithelial and stromal cells associated with TP53 haploinsufficiency, as well as interlocking pathways. Notably, a dysregulated p53 signaling pathway was readily detectable. Pharmacological intervention with the p53 rescue compounds CP-31398 and PRIMA-1 provided further evidence in support of the central role of p53 in affecting these changes in LFS cells and treatment for this cancer. Because loss of signaling mediated by TP53 is associated with the development and survival of many human tumors, identification of gene expression profiles in morphologically normal cells that carry "one-hit" p53 mutations may reveal novel biomarkers, enabling the discovery of potential targets for chemoprevention of sporadic tumors as well.

Distress in partners of individuals diagnosed with or at high risk of developing tumors due to rare hereditary cancer syndromes

OBJECTIVE

Li Fraumeni syndrome (LFS) and Von Hippel-Lindau disease (VHL) are two rare hereditary tumor syndromes, characterized by a high risk of developing multiple tumors at various sites and ages for which preventive and treatment options are limited. For partners, it may be difficult to deal with the on-going threat of tumors in both their spouse and children. Therefore, this study aims to evaluate the prevalence of and factors associated with psychological distress among partners of individuals with or at high risk of LFS or VHL.

METHODS

As part of a nationwide, cross-sectional study, partners of individuals diagnosed with or at high risk of LFS or VHL were invited to complete a self-report questionnaire assessing distress, worries, and health-related quality of life.

RESULTS

Fifty-five (58%) of those high-risk individuals with a partner consented to having their partner approached for the study. In total, 50 partners (91%) completed the questionnaire, of whom 28% reported clinically relevant levels of syndrome-related distress. Levels of distress and worries of the partners and their high-risk spouse were significantly correlated. Younger age and a lack of social support were also associated significantly with heightened levels of distress and worries. The majority of partners (76%) believed that professional psychosocial support should be routinely offered to them.

CONCLUSIONS

Approximately one-quarter of the partners exhibit clinically relevant levels of distress that warrant psychological support. The distress levels of the 'patient' could potentially be used to identify partners at risk of developing clinically relevant levels of distress.

CREG1 enhances p16(INK4a) -induced cellular senescence

Cellular senescence is an irreversible growth arrest that is activated in normal cells upon shortening of telomere and other cellular stresses. Bypassing cellular senescence is a necessary step for cells to become immortal during oncogenic transformation. During the spontaneous immortalization of Li-Fraumeni Syndrome (LFS) fibroblasts, we found that CREG1 (Cellular Repressor of E1A-stimulated Genes 1) expression was decreased during immortalization and increased in senescence. Moreover, we found that repression of CREG1 expression occurs via an epigenetic mechanism, promoter DNA methylation. Ectopic expression of CREG1 in the immortal LFS cell lines decreases cell proliferation but does not directly induce senescence. We confirmed this in osteosarcoma and fibrosarcoma cancer cell lines, cancers commonly seen in Li-Fraumeni Syndrome. In addition, we found that p16 (INK4a) is also downregulated in immortal cells and that coexpression of CREG1 and p16 (INK4a) , an inhibitor of CDK4/6 and Rb phosphorylation, has a greater effect than either CREG1 and p16 (INK4a) alone to reduce cell growth, induce cell cycle arrest and cellular senescence in immortal LFS fibroblasts, osteosarcoma and fibrosarcoma cell lines. Moreover, cooperation of CREG1 and p16 (INK4a) inhibits the expression of cyclin A and cyclin B by inhibiting promoter activity thereby decreasing mRNA and protein levels; these proteins are required for S-phase entry and G2/M transition. In conclusion, this is the first evidence to demonstrate that CREG1 enhances p16 (INK4a) -induced senescence by transcriptional repression of cell cycle-regulated genes.

Germline mutations in cancer susceptibility genes: an overview for nurses

OBJECTIVE

To provide an overview of hereditary cancer susceptibility genes and associated cancer risks.

DATA SOURCES

Peer reviewed published research studies and review articles.

CONCLUSIONS

Identifying deleterious mutations in cancer susceptibility genes allows for clarification of cancer risk in individual family members and risk-level appropriate screening, and risk management recommendations. Evolving knowledge of the role of germline mutations provides an unprecedented opportunity to reduce cancer incidence, morbidity, and morality.

IMPLICATIONS FOR NURSING PRACTICE

To provide individuals/families with accurate cancer risk management information and guidance, oncology nurses must be familiar with scientific discoveries related to cancer susceptibility genes.

A molecular signature of normal breast epithelial and stromal cells from Li-Fraumeni syndrome mutation carriers

Specific changes in gene expression during cancer initiation should enable discovery of biomarkers for risk assessment, early detection and targets for chemoprevention. It has been previously demonstrated that altered mRNA and proteome signatures of morphologically normal cells bearing a single inherited "hit" in a tumor suppressor gene parallel many changes observed in the corresponding sporadic cancer. Here, we report on the global gene expression profile of morphologically normal, cultured primary breast epithelial and stromal cells from Li-Fraumeni syndrome (LFS) TP53 mutation carriers. Our analyses identified multiple changes in gene expression in both morphologically normal breast epithelial and stromal cells associated with TP53 haploinsufficiency, as well as interlocking pathways. Notably, a dysregulated p53 signaling pathway was readily detectable. Pharmacological intervention with the p53 rescue compounds CP-31398 and PRIMA-1 provided further evidence in support of the central role of p53 in affecting these changes in LFS cells and treatment for this cancer. Because loss of signaling mediated by TP53 is associated with the development and survival of many human tumors, identification of gene expression profiles in morphologically normal cells that carry "one-hit" p53 mutations may reveal novel biomarkers, enabling the discovery of potential targets for chemoprevention of sporadic tumors as well.

Understanding DNA damage response and DNA repair pathways: applications to more targeted cancer therapeutics

Radiation therapy and many of the commonly used cancer chemotherapeutic drugs target DNA for cytotoxicity. Indeed, the subsequent DNA damage response (DDR) to these cancer treatments in both malignant and normal cells/tissues determines the therapeutic index (TI) of the treatment. The DDR is a complex set of cell processes involving multiple DNA repair, cell cycle regulation, and cell death/survival pathways (or networks) with both damage specificity and coordination of the DDR to different types of DNA damage. Over the last decade, significant progress has been made in elucidating these complex cellular and molecular networks involved in the DDR in human tumor and normal tissues. Based on what has been learned about these processes using experimental in vitro and in vivo models, DDR and DNA pathways are now potential targets for cancer therapy. This article presents an overview of our current understanding of the DDR, including the key DNA repair pathways involved in determining the cytotoxicity to several classes of chemotherapy drugs (CT) as well as ionizing radiation (IR). Since many different types of human cancers can arise from genetic or epigenetic changes in the DDR and DNA repair pathways, this article also covers recent developments in cancer therapeutics that attempt to target these specific tumor-related DDR/DNA repair defects as monotherapy or, more commonly, when combined with conventional cancer treatments.

Li-Fraumeni syndrome: the genetics and treatment considerations for the sarcoma and associated neoplasms

Li-Fraumeni syndrome is an autosomal dominant disorder first reported by Drs Li and Fraumeni in 1969. Malkin was the first to describe a germline mutation as an underlying defect of Li-Fraumeni syndrome. Cancer risk in mutation carriers has been estimated to be 50% by age 40 and 90% by age 60. Children of affected parents have an approximate 50% risk of inheriting the familial mutation. Functional assays have been established that allow for easy genetic testing for TP53 mutation. Treatment goals center on early detection and surgical resection of affected organ. Targeted therapy for the TP53 gene may hold promise for the future.

Potential of Advexin: a p53 gene-replacement therapy in Li-Fraumeni syndrome

Li-Fraumeni syndrome is a rare autosomal dominant cancer predisposition syndrome. The majority of families fulfilling definition of Li-Fraumeni syndrome demonstrate inherited abnormalities involving the p53 gene. Cells with dysfunctional p53 are predisposed to the development of cancer phenotype. Advexin (Introgen Therapeutics Inc., TX, USA) is an adenoviral-based experimental therapeutic that provides delivery of wild-type p53 to cancer cells and demonstrates anticancer activity following adequate expression of p53. Theoretically, correction of p53 function in cancer developing in patients with Li-Fraumeni syndrome through treatment with Advexin will provide anti-tumor activity. One patient with Li-Fraumeni syndrome has been reported to have responded to Advexin. This review will summarize background knowledge of Li-Fraumeni syndrome, mechanisms of Advexin and clinical response of cancer to Advexin with a focus on Li-Fraumeni syndrome.

A novel splice mutation in the TP53 gene associated with Leydig cell tumor and primitive neuroectodermal tumor

A 20-month-old boy presented with precocious puberty due to a Leydig cell tumor, and at the age of 6 years with a primitive neuroectodermal brain-tumor (PNET). A novel splice site mutation of the TP53-gene, likely to be associated with a nonfunctional protein, was found in the proband, his father and younger sister, but only the proband has so far developed malignancy. The clinical phenotype in the boy is suggestive of Li-Fraumeni syndrome, but the family does not strictly conform to the canonical definition.

Malignant triton tumor in a patient with Li-Fraumeni syndrome and a novel TP53 mutation

We report a 3-year-old boy with a malignant triton tumor (MTT) involving the left masticator space with local invasion and regional lymph node metastasis. Family history and detection of a novel germline TP53 mutation confirmed his diagnosis of Li Fraumeni syndrome (LFS). MTT has not been previously described in association with LFS. This case along with a comprehensive review of the literature, illustrate the importance of both somatic and germline TP53 mutations in the pathogenesis MTT. The tumor could not be resected and he was successfully treated with intensive induction chemotherapy, irradiation, and high-dose chemotherapy with autologous stem cell transplantation.

p53 and disease: when the guardian angel fails

The p53 tumor suppressor gene (TP53) is mutated more often in human cancers than any other gene yet reported. Of importance, it is mutated frequently in the common human malignancies of the breast and colorectum and also, but less frequently, in other significant human cancers such as glioblastomas. There is also one inherited cancer predisposing syndrome called Li-Fraumeni that is caused by TP53 mutations. In this review, we discuss the significance of p53 mutations in some of the above tumors with a view to outlining how p53 contributes to malignant progression. We also discuss the usefulness of TP53 status as a prognostic marker and its role as a predictor of response to therapy. Finally, we outline some evidence that abnormalities in p53 function contribute to the etiology of other non-neoplastic diseases.

Is there a role for PCR-SSCP among the methods for missense mutation detection of TP53 gene?

Mutation analysis methods have increased in variety during the past years. High-throughput microarray methods have especially increased in popularity. However, new methods require reference points, and not all of the methods are equal in sensitivity and specificity. Furthermore, the detection of unknown missense mutations, such as unknown TP53 mutations in human tumors, for clinical purposes requires great accuracy, which may be difficult to acquire with the current high-throughput methods. For these reasons, the classical methods, such as PCR-manual sequencing and PCR-SSCP, are still valuable and necessary.

Hereditary urological cancer syndromes

Hereditary urological cancer syndromes are rare, but it is important that they are recognized because they have important prognostic implications; prompt diagnosis can dramatically improve patient outcomes. The urologist or urological oncologist should, therefore, ascertain which tumors of the many seen in clinical practice warrant referral for the opinion of a clinical geneticist. Despite the aggressive natural history of most inherited urological cancer syndromes, organ-preserving treatments are desirable because these syndromes predispose affected patients to the formation of multifocal and metachronous tumors. Identification of the molecular mechanisms that underlie carcinogenesis in both familial and sporadic urological cancers has, in some cases, resulted in novel and specifically targeted approaches to therapy. Patients who present with early-onset or multiple tumors should be carefully investigated for the presence of a hereditary cancer syndrome, and once a diagnosis is made, appropriate screening should be instigated for family members to enable early detection of tumors both within and outside the urogenital tract.

Reassessing the role of p53 in cancer and ageing from an evolutionary perspective

The gene p53 has been fashioned as the guardian of the genome and as prototype of the tumour suppressor gene (TSG) whose function must be inactivated in order for tumours to develop. The ubiquitous expression of truncated p53 protein isoforms, results in "premature ageing" of laboratory mouse strains engineered for expressing such isoforms. These facts have been construed in the argument that p53 evolved in order to protect organisms with renewable tissues from developing cancer yet, because p53 is also an inducer of cellular senescence or apoptosis after extensive DNA damage, it becomes a limiting factor for tissue renewal by depleting tissues from stem/precursor cells thus leading to whole-organism ageing. From that point of view p53 displays antagonist pleiotropy contributing to the establishment of degenerative diseases and ageing. Therefore, tumour suppression becomes a balancing act between cancer prevention and ageing. Nevertheless, here we present current evidence showing that the aforementioned argument is rather inconsistent and unwarranted on evolutionary grounds. The evolutionary perspective indicates that p53 evolved so as to play a subtle but very important role during development while its role as a TSG is only important in animals that are protected from most sources of extrinsic mortality, thus suggesting that p53 was primarily selected for its developmental role and not as a TSG. Therefore no real antagonist pleiotropy can be attached to p53 functions and their relationship with whole-organism ageing might be a laboratory artefact.

Les gliomes multiples : étude clinique et hypothèses physiopathologiques

INTRODUCTION

Although a rare entity, multiple gliomas must be recognized and distinguished from other causes of multiple brain lesions.

METHODS

Clinical and radiological features of 33 multiple gliomas were reviewed, including 20 synchronous cases and 13 metachronous cases.

RESULTS

In 17 patients, radiological features were highly suggestive of spread from a primary site (multifocal gliomas). No apparent dissemination route was identified in the other cases which were presumed to be multicentric gliomas. For nine patients (27 percent), a second neoplasia or cancer was found in first degree relatives suggesting a genetic predisposition. Overall median survival was 79 weeks (64 weeks for glioblastomas). The age at onset was the main prognostic factor.

CONCLUSION

Multiple gliomas represent a heterogeneous entity, probably corresponding to different mechanisms. In our group, survival was comparable to unique glioma.

p53 autoantibodies from patients with head and neck cancer recognise common epitopes on the polypeptide chain of p53

In the present study, we analysed p53 autoantibodies from patients with head and neck cancer by ELISA, by Western blot using C- and N-terminal fragments of p53 and with peptide libraries of p53. We found that 8.2% of the patients with head and neck cancer developed antibodies against p53. Using additional p53 autoantibody-positive sera from patients with head and neck cancer, we found that all of these sera recognised common epitopes, which were also recognised by well-known mouse monoclonal antibodies against p53. Common epitopes are located in regions on the polypeptide chain of p53, which are functionally important for the role of p53 in growth control. Thus, the knowledge of these epitopes might be useful for the development of new strategies for cancer therapy.

Impact of the MDM2 SNP309 and p53 Arg72Pro polymorphism on age of tumour onset in Li-Fraumeni syndrome

Li-Fraumeni syndrome, resulting from p53 (TP53) germline mutations, represents one of the most devastating genetic predispositions to cancer. Recently, the MDM2 SNP309 (T-->G variation) was shown to be associated with accelerated tumour formation in p53 mutation carriers. The impact of the common p53 codon 72 polymorphism on cancer risk remains controversial. We therefore investigated the effect of these two polymorphisms in 61 French carriers of the p53 germline mutation. The mean age of tumour onset in MDMD2 SNP309 G allele carriers (19.6 years) was significantly different from that observed in patients homozygous for the T allele (29.9 years, p<0.05). For the p53 codon 72 polymorphism, the mean age of tumour onset in Arg allele carriers (21.8 years) was also different from that of Pro/Pro patients (34.4 years, p<0.05). We observed a cumulative effect of both polymorphisms because the mean ages of tumour onset in carriers of the MDM2G and p53Arg alleles (16.9 years) and those with the MDM2T/T and p53Pro/Pro genotypes (43 years) were clearly different (p<0.02). Therefore, our results confirm the impact of the MDM2 SNP309 G allele on the age of tumour onset in germline p53 mutation carriers, and suggest that this effect may be amplified by the p53 72Arg allele. Polymorphisms affecting p53 degradation therefore represent one of the rare examples of modifier genetic factors identified to date in mendelian predispositions to cancer.

Familial gastric cancers with Li-Fraumeni Syndrome: A case repast

We report a case of the rare solid-pseudopapillary tumor of the pancreas. In contrast to other.

Survivin-directed RNA interference cocktail is a potent suppressor of tumour growth in vivo

BACKGROUND

Survivin is proposed to play a central role in the progression and resistance to therapy of diverse tumour types. High levels of this molecule in tumour cells also correlate with loss of the TP53 tumour suppressor gene, suggesting a molecular connection between TP53 loss and transcriptional induction of Survivin. Patients with TP53 germline mutations, such as those with Li-Fraumeni syndrome, are particularly susceptible to sarcomas, including rhabdomyosarcomas. Our study aimed to identify rhabdomyosarcoma tumours that express Survivin, in order to test novel Survivin-targeted therapies in these tumours.

METHODS

Tumour microarray slides composed of 63 primary rhabdomyosarcoma tumours were stained with a polyclonal antibody to Survivin to identify tumours expressing Survivin. Subcutaneous tumours were then established in NOD/SCID mice using RH30(red) cells, a red fluorescent clone of the RH30 human alveolar rhabdomyosarcoma cell line. Tumours were treated by hydrodynamic injection with a cocktail of Survivin-shRNA-encoding plasmids for a period of 2 weeks.

RESULTS

Over 80% of primary rhabdomyosarcoma tumours expressed Survivin. Treatment of rhabdomyosarcoma xenografts showed greater than 70% reduction in growth when compared with control injected tumours at study completion (average tumour sizes: 1683 v 304 mm3, p<0.05).

CONCLUSIONS

Our findings support a role for Survivin in rhabdomyosarcoma biology and provide preliminary evidence for the therapeutic use of Survivin-targeted RNA interference for human tumours that express high levels of this molecule.

p53 is a suppressor of inflammatory response in mice

Chronic inflammation is known to promote cancer, suggesting that negative regulation of inflammation is likely to be tumor suppressive. We found that p53 is a general inhibitor of inflammation that acts as an antagonist of nuclear factor kappaB (NFkappaB). We first observed striking similarities in global gene expression profiles in human prostate cancer cells LNCaP transduced with p53 inhibitory genetic element or treated with TNF, suggesting that p53 inhibits transcription of TNF-inducible genes that are largely regulated by NFkappaB. Consistently, ectopically expressed p53 acts as an inhibitor of transcription of NFkappaB-dependent promoters. Furthermore, suppression of inflammatory response by p53 was observed in vivo in mice by comparing wild-type and p53 null animals at molecular (inhibition of transcription of genes encoding cytokines and chemokines, reducing accumulation of reactive oxygen species and protein oxidation products), cellular (activation of macrophages and neutrophil clearance) and organismal (high levels of metabolic markers of inflammation in tissues of p53-deficient mice and their hypersensitivity to LPS) levels. These observations indicate that p53, acting through suppression of NFkappaB, plays the role of a general "buffer" of innate immune response in vivo that is well consistent with its tumor suppressor function and frequent constitutive activation of NFkappaB in tumors.

A TP53-truncating germline mutation (E287X) in a family with characteristics of both hereditary diffuse gastric cancer and Li-Fraumeni syndrome

Mutations in CDH1, which encodes E-cadherin, have been associated with hereditary diffuse gastric cancer (HDGC) in Western populations but have not been shown to play a major role in Asians. Recently, a patient with familial gastric cancer (FGC) was shown to harbor a germline mutation in the TP53 gene, which encodes p53 and has been previously associated with Li-Fraumeni Syndrome (LFS). To determine whether mutations in TP53 are associated with FGC in Asians, we screened the entire coding region of TP53 in probands from 23 Korean FGC families. We identified a nonsense (E287X) TP53 germline mutation in a family whose history is compatible with both HDGC and LFS. Two members of this family (SNU-G2) were afflicted with brain tumors, seven with gastric cancers, two with sarcomas, and one with both gastric cancer and a sarcoma. The E287X TP53 mutation segregated with the cancer phenotype in the family members from whom DNA samples were available. To our knowledge, this is the first report of a large family with both HDGC and LFS. Our results suggest that TP53 mutational screening in FGC families should be interpreted with caution because additional TP53 mutation-carrying HDGC families may also show LFS-related phenotypes.

Multifocal intrafollicular granulosa cell tumor of the ovary associated with an unusual germline p53 mutation

A 23-year-old woman presented with a 7 cm right multicystic mass in the ovary, which corresponded microscopically to an unusual lesion consisting of a multifocal granulosa cell tumor with intrafollicular ('in situ') growth involving two-thirds of mature follicles. Stromal invasion was found in only one area where neoplastic follicles coalesced. Granulosa cells had atypical, bizarre TP53 positive nuclei with hyperchromatism, abundant mitoses and numerous hyaline globules. The contralateral ovary was normal. From the age of 10 years, the patient had a complex medical history of multiple tumors, including telangiectatic osteosarcoma, typical and malignant phyllodes tumor, reticulohistiocytoma of skin, carcinomas of the breast and lipo- and leiomyosarcoma. The female genital tract also harbored myometrial leiomyomas and an early endometrial carcinoma. Retrospective histologic study of all mesenchymal neoplasms in this patient showed, the conspicuous presence of similar bizarre TP53 positive cells with hyaline globules in all the mesenchymal neoplasms. In the genetic study, a germline p53 gene mutation was detected in exon 10, codon 336, generating a stop codon in the oligomerization domain of the protein (E336X). A further p53 mutation was found in exon 7 in the granulosa cell tumor. Mutation occurred de novo since there was no history of tumors in any family members, all of whom had a wild-type p53. Although this patient shows a typical tumor phenotype of Li Fraumeni syndrome, the germline mutation corresponded to a highly unusual mutated domain, which is similar to the one found in childhood malignant adrenocortical tumor; also a rare neoplasm that originates in adrenocortical cells; which are closely related, both functionally and embryologically, to granulosa cells.

Multistep tumorigenesis and the microenvironment

Early-stage cancers have long been considered to be less aggressive than late-stage cancers because it is assumed that they have accumulated fewer of the mutations that are required for full metastatic potential. For breast cancer, recent gene expression profiling data have challenged this paradigm by identifying early-stage cancers with similar gene expression profiles to fully metastatic cancers. In this review, multistep carcinogenesis is reconsidered in light of these new data. The concept that the tumor stroma plays a key role in determining whether a metastatic tumor cell will remain dormant or become invasive is discussed. Recent studies demonstrating the feasibility of targeting tumor stroma for cancer prevention and treatment are presented.

Increased predisposition to cancer in brothers and offspring of testicular tumor patients

Cancer susceptibility was examined in first-degree relatives of 293 testicular tumor patients (TTPs) and 586 age-matched healthy males. Significantly increased risk was found in the families of TTPs (OR: 1.4; CI: 1.08-1.79), however, except for testicular cancer of 7 brothers (OR: 11.7; CI: 1.42-256.5), and 6 various childhood tumors (bilateral Wilms' tumor, neuroblastoma, medulloblastoma, ALL, histiocytosis-X, testicular tumor) of 200 offspring (OR: 12.9; CI: 1.54-286.2), no association with other malignancies was observed. No differences were seen between the fertility of patients and controls when occupational or socio-economic status of the families was taken into account. However, the majority of the controls (85%) fathered the first child between 20-30 years of age, while only 61% of TTPs had the first child in the same age group. TTPs fathered more girls than boys (P=0.009), and the lower male - higher female ratio of index children was also identical, irrespective of the conception taking place before or after the father's treatment. Occupations did not, but smoking might have influenced cancer susceptibility of the patients. Aggregation of fraternal testicular tumors, and both dramatically increased cancer risk and altered sex ratio of the offspring indicate a remarkable role of hereditary factors in tumorigenesis and later consequences of a certain portion of testicular malignancies, which must be refined by molecular studies.

Germline TP53 mutations and Li-Fraumeni syndrome

There are now reports of nearly 250 independent germline TP53 (p53) mutations in over 100 publications. Such mutations are typically associated with Li-Fraumeni or Li-Fraumeni-like syndrome, although many have been identified in cohorts of patients with tumors considered to be typical of LFS. In general, the spectrum of mutations that has been detected in the germline reflects that found in tumors, although there are some notable exceptions in certain tumor types. Detailed knowledge of the pedigrees allows a comprehensive analysis of genotype-phenotype correlations and an understanding of the tumors that are associated with germline TP53 mutations. This review will discuss the spectrum of mutations and the methods for mutation detection, the tumors associated with inheritance of a germline mutation, and some of the ethical and clinical problems in patients with a germline TP53 mutation.

Screening for TP53 rearrangements in families with the Li-Fraumeni syndrome reveals a complete deletion of the TP53 gene

The absence of detectable germline TP53 mutations in a fraction of families with Li-Fraumeni syndrome (LFS) has suggested the involvement of other genes, but this hypothesis remains controversial. The density of Alu repeats within the TP53 gene led us to search genomic rearrangements of TP53 in families without detectable TP53 mutation. To this aim, we adapted the quantitative multiplex PCR of short fluorescent fragments (QMPSF) method to the analysis of the 11 exons of TP53. We analysed 98 families, either fulfilling (six families) or partially meeting (92 families) the criteria for LFS, and in which classical methods had failed to reveal TP53 alterations. We identified, in a large family fulfilling the criteria for LFS, a complete heterozygous deletion of TP53. Additional QMPSF analyses indicated that this deletion, which partially removed the centromeric FLJ10385 locus, covered approximately 45 kb. This deletion was shown to result from a complex rearrangement involving two distinct Alu-mediated recombinations. We conclude that TP53 germline rearrangements occur as rare events, but must be considered in LFS families without detectable point TP53 mutation.