Why otolaryngologists need to be aware of Fanconi anemia

Concepts of multi-level dynamical modelling: understanding mechanisms of squamous cell carcinoma development in Fanconi anemia

Fanconi anemia (FA) is a rare disease (incidence of 1:300,000) primarily based on the inheritance of pathogenic variants in genes of the FA/BRCA (breast cancer) pathway. These variants ultimately reduce the functionality of different proteins involved in the repair of DNA interstrand crosslinks and DNA double-strand breaks. At birth, individuals with FA might present with typical malformations, particularly radial axis and renal malformations, as well as other physical abnormalities like skin pigmentation anomalies. During the first decade of life, FA mostly causes bone marrow failure due to reduced capacity and loss of the hematopoietic stem and progenitor cells. This often makes hematopoietic stem cell transplantation necessary, but this therapy increases the already intrinsic risk of developing squamous cell carcinoma (SCC) in early adult age. Due to the underlying genetic defect in FA, classical chemo-radiation-based treatment protocols cannot be applied. Therefore, detecting and treating the multi-step tumorigenesis process of SCC in an early stage, or even its progenitors, is the best option for prolonging the life of adult FA individuals. However, the small number of FA individuals makes classical evidence-based medicine approaches based on results from randomized clinical trials impossible. As an alternative, we introduce here the concept of multi-level dynamical modelling using large, longitudinally collected genome, proteome- and transcriptome-wide data sets from a small number of FA individuals. This mechanistic modelling approach is based on the "hallmarks of cancer in FA", which we derive from our unique database of the clinical history of over 750 FA individuals. Multi-omic data from healthy and diseased tissue samples of FA individuals are to be used for training constituent models of a multi-level tumorigenesis model, which will then be used to make experimentally testable predictions. In this way, mechanistic models facilitate not only a descriptive but also a functional understanding of SCC in FA. This approach will provide the basis for detecting signatures of SCCs at early stages and their precursors so they can be efficiently treated or even prevented, leading to a better prognosis and quality of life for the FA individual.

Impact of Epigenetics on Complications of Fanconi Anemia: The Role of Vitamin D-Modulated Immunity

Fanconi anemia (FA) is a rare disorder with the clinical characteristics of (i) specific malformations at birth, (ii) progressive bone marrow failure already during early childhood and (iii) dramatically increased risk of developing cancer in early age, such as acute myeloid leukemia and squamous cell carcinoma. Patients with FA show DNA fragility due to a defect in the DNA repair machinery based on predominately recessive mutations in 23 genes. Interestingly, patients originating from the same family and sharing an identical mutation, frequently show significant differences in their clinical presentation. This implies that epigenetics plays an important role in the manifestation of the disease. The biologically active form of vitamin D, 1α,25-dihydroxyvitamin D₃ controls cellular growth, differentiation and apoptosis via the modulation of the immune system. The nuclear hormone activates the transcription factor vitamin D receptor that affects, via fine-tuning of the epigenome, the transcription of >1000 human genes. In this review, we discuss that changes in the epigenome, in particular in immune cells, may be central for the clinical manifestation of FA. These epigenetic changes can be modulated by vitamin D suggesting that the individual FA patient’s vitamin D status and responsiveness are of critical importance for disease progression.

Diagnostic accuracy of brush biopsy-based cytology for the early detection of oral cancer and precursors in Fanconi anemia

BACKGROUND

Individuals with Fanconi anemia (FA) have a 500-fold to 700-fold elevated risk, much earlier onset, and limited therapeutic options for oral squamous cell carcinoma (SCC) compared with the general population. The early detection of SCC, or preferably its precursors, is mandatory to retain curative therapeutic options. Due to frequent synchronic and metachronic oral lesions, tissue biopsies, as usually recommended by guidelines, often are not feasible. In the current study, an alternative strategy for early detection using oral brush biopsy-based cytology was validated regarding its diagnostic accuracy.

METHODS

Over a 12-year period, the oral cavities of a large cohort of 713 individuals with FA were inspected systematically and brush biopsy-based cytology of 1233 visible oral lesions was performed. In cases of inconclusive cytology, analysis of DNA ploidy was performed whenever possible. The results were correlated to a long-term clinicopathological follow-up reference standard.

RESULTS

A total of 737 lesions were suitable for statistical analysis, including 86 lesions with at least high-grade oral epithelial dysplasia in 30 patients. For cytology, the sensitivity and specificity were 97.7% and 84.5%, respectively. Additional analysis of DNA ploidy increased the sensitivity and specificity to 100% and 92.2%, respectively.

CONCLUSIONS

Careful inspection of the oral cavity of individuals with FA followed by brush biopsy-based cytology appears to identify visible oral, potentially malignant and malignant lesions that warrant treatment. Approximately 63% of SCC and precursor lesions are detected at a noninvasive or early stage. Negative cytology or a lack of DNA aneuploidy can exclude high-grade oral epithelial dysplasia or SCC with high accuracy and thus reduce the need for invasive diagnostic biopsies.

Dental-craniofacial manifestation and treatment of rare diseases

Rare diseases are usually genetic, chronic and incurable disorders with a relatively low incidence. Developments in the diagnosis and management of rare diseases have been relatively slow due to a lack of sufficient profit motivation and market to attract research by companies. However, due to the attention of government and society as well as economic development, rare diseases have been gradually become an increasing concern. As several dental-craniofacial manifestations are associated with rare diseases, we summarize them in this study to help dentists and oral maxillofacial surgeons provide an early diagnosis and subsequent management for patients with these rare diseases.

A Review of Fanconi Anemia for the Practicing Pediatrician

Early recognition of a patient who might have Fancomi anemia by the general pediatrician and referral to a tertiary care center with a dedicated cancer risk program is critical for early diagnosis. Genetic testing and close multidisciplinary surveillance is required for patients with this syndrome and their families because of its multisystem involvement and propensity for early-onset bone marrow failure and leukemic transformation. This article reviews the clinical symptoms and signs, radiologic findings, and screening guidelines of FA for the general pediatrician.

Noninvasive molecular screening for oral precancer in Fanconi anemia patients

LOH at chromosome arms 3p, 9p, 11q, and 17p are well-established oncogenetic aberrations in oral precancerous lesions and promising biomarkers to monitor the development of oral cancer. Noninvasive LOH screening of brushed oral cells is a preferable method for precancer detection in patients at increased risk for head and neck squamous cell carcinoma (HNSCC), such as patients with Fanconi anemia. We determined the prevalence of LOH in brushed samples of the oral epithelium of 141 patients with Fanconi anemia and 144 aged subjects, and studied the association between LOH and HNSCC. LOH was present in 14 (9.9%) nontransplanted patients with Fanconi anemia, whereas LOH was not detected in a low-risk group (n = 50, >58 years, nonsmoking/nonalcohol history) and a group with somewhat increased HNSCC risk (n = 94, >58 years, heavy smoking/excessive alcohol use); Fisher exact test, P = 0.023 and P = 0.001, respectively. Most frequent genetic alteration was LOH at 9p. Age was a significant predictor of LOH (OR, 1.13, P = 0.001). Five patients with Fanconi anemia developed HNSCC during the study at a median age of 39.6 years (range, 24.8-53.7). LOH was significantly associated with HNSCC (Fisher exact test, P = 0.000). Unexpectedly, the LOH assay could not be used for transplanted patients with Fanconi anemia because donor DNA in brushed oral epithelium, most likely from donor leukocytes present in the oral cavity, disturbed the analysis. Noninvasive screening using a LOH assay on brushed samples of the oral epithelium has a promising outlook in patients with Fanconi anemia. However, assays need to be adapted in case of stem cell transplantation, because of contaminating donor DNA.

Oral human papillomavirus is common in individuals with Fanconi anemia

BACKGROUND

Fanconi anemia is a rare genetic disorder resulting in a loss of function of the Fanconi anemia-related DNA repair pathway. Individuals with Fanconi anemia are predisposed to some cancers, including oropharyngeal and gynecologic cancers, with known associations with human papillomavirus (HPV) in the general population. As individuals with Fanconi anemia respond poorly to chemotherapy and radiation, prevention of cancer is critical.

METHODS

To determine whether individuals with Fanconi anemia are particularly susceptible to oral HPV infection, we analyzed survey-based risk factor data and tested DNA isolated from oral rinses from 126 individuals with Fanconi anemia and 162 unaffected first-degree family members for 37 HPV types.

RESULTS

Fourteen individuals (11.1%) with Fanconi anemia tested positive, significantly more (P = 0.003) than family members (2.5%). While HPV prevalence was even higher for sexually active individuals with Fanconi anemia (17.7% vs. 2.4% in family; P = 0.003), HPV positivity also tended to be higher in the sexually inactive (8.7% in Fanconi anemia vs. 2.9% in siblings). Indeed, having Fanconi anemia increased HPV positivity 4.9-fold (95% CI, 1.6-15.4) considering age and sexual experience, but did not differ by other potential risk factors.

CONCLUSION

Our studies suggest that oral HPV is more common in individuals with Fanconi anemia. It will be essential to continue to explore associations between risk factors and immune dysfunction on HPV incidence and persistence over time.

IMPACT

HPV vaccination should be emphasized in those with Fanconi anemia as a first step to prevent oropharyngeal cancers, although additional studies are needed to determine whether the level of protection it offers in this population is adequate.