Noninvasive molecular screening for oral precancer in Fanconi anemia patients

The onset and progression of oral potentially malignant disorders in Fanconi anemia patients: Highlighting early detection of oral cancer

In 2020, Fanconi anemia (FA) was classified as a syndrome with insufficient epidemiological evidence in the oral potentially malignant disorder (OPMD) group by the WHO Collaborating Centre. The paucity of case reports on FA-associated OPMD limits evidence-based management, and such cases have not been analyzed collectively in detail. Hence, the objective of this short communication is to summarize the evidence on the onset and progression of OPMD in FA patients, so as to better understand the natural history of oral cancer development in patients affected by FA. A total of 11 eligible papers containing 1332 FA patients are involved in onset and progression of OPMD in FA patients. Of these, 186 (14.0%) were diagnosed with OPMD. With available data from 4 follow-up studies, 30 (41.1%) of 73 FA patients compatible with OPMD further developed into OSCC at young age (10-30 years old). The evidence on FA with malignant potential comprise clinical epidemiology, oral cytology abnormalities, DNA aneuploidy, loss of autofluorescence, loss of heterozygosity, high-risk human papillomavirus infection, DNA mutations in saliva and plasma samples. Collectively, these can consummate the evidence on FA as a syndrome that may potentiate cancer development in oral cavity mentioned by the WHO. Importantly, it highlights close surveillance is instrumental for FA patients with OPMD to early detect oral cancer.

Oral cancer prediction by noninvasive genetic screening

Oral squamous cell carcinomas (OSCCs) develop in genetically altered epithelium in the mucosal lining, also coined as fields, which are mostly not visible but occasionally present as white oral leukoplakia (OL) lesions. We developed a noninvasive genetic assay using next-generation sequencing (NGS) on brushed cells to detect the presence of genetically altered fields, including those that are not macroscopically visible. The assay demonstrated high accuracy in OL patients when brush samples were compared with biopsies as gold standard. In a cohort of Fanconi anemia patients, detection of mutations in prospectively collected oral brushes predicted oral cancer also when visible abnormalities were absent. We further provide insight in the molecular landscape of OL with frequent changes of TP53, FAT1 and NOTCH1. NGS analysis of noninvasively collected samples offers a highly accurate method to detect genetically altered fields in the oral cavity, and predicts development of OSCC in high-risk individuals. Noninvasive genetic screening can be employed to screen high-risk populations for cancer and precancer, map the extension of OL lesions beyond what is visible, map the oral cavity for precancerous changes even when visible abnormalities are absent, test accuracy of promising imaging modalities, monitor interventions and determine genetic progression as well as the natural history of the disease in the human patient.

Development of a mouse model for spontaneous oral squamous cell carcinoma in Fanconi anemia

Fanconi anemia (FA) patients frequently develop oral squamous cell carcinoma (OSCC). This cancer in FA patients is diagnosed within the first 3-4 decades of life, very often preceded by lesions that suffer a malignant transformation. In addition, they respond poorly to current treatments due to toxicity or multiple recurrences. Translational research on new chemopreventive agents and therapeutic strategies has been unsuccessful partly due to scarcity of disease models or failure to fully reproduce the disease. Here we report that Fanca gene knockout mice (Fanca^-/-) frequently display pre-malignant lesions in the oral cavity. Moreover, when these animals were crossed with animals having conditional deletion of Trp53 gene in oral mucosa (K14cre;Trp53^F2-10/F2-10), they spontaneously developed OSCC with high penetrance and a median latency of less than ten months. Tumors were well differentiated and expressed markers of squamous differentiation, such as keratins K5 and K10. In conclusion, Fanca and Trp53 genes cooperate to suppress oral cancer in mice, and Fanca^-/-;K14cre;Trp53^F2-10/F2-10 mice constitute the first animal model of spontaneous OSCC in FA.

A New Multi-Color FISH Assay for Brush Biopsy-Based Detection of Chromosomal Aneuploidy in Oral (Pre)Cancer in Patients with Fanconi Anemia

BACKGROUND

Fanconi anemia (FA) is a rare inherited DNA instability disorder with a remarkably elevated risk of oral squamous cell carcinoma. These cancers can be detected with oral brush biopsy-based cytology even at early stages. This study aims to determine the diagnostic accuracy of a new multi-color fluorescent in situ hybridization (FISH) assay consisting of probes for CCND1, TERC, MYC and centromere of chromosome 6, as well as a 9p21 FISH assay consisting of probes for CDKN2A and centromere of chromosome 9 for the detection of oral (pre) malignant lesions in FA.

METHODS

(I) Cutoffs for the dichotomization of positive or negative multi-color FISH results are determined and (II) retrospectively validated by using archived oral brush biopsy specimens from individuals with Fanconi anemia. In addition, the specimens for cutoff determination were re-hybridized with the 9p21 FISH assay.

RESULTS

A cutoff of six or more chromosomal aneuploid cells for a positive FISH result was determined in the cutoff study on 160 biopsy specimens. The validating of this cutoff on 152 specimens showed at best a sensitivity of 87% and a specificity of 82.9%.

CONCLUSION

Multi-color FISH is a sufficient tool to detect chromosomal aneuploidy in oral (pre) malignant lesions of individuals with Fanconi anemia. However, some false positive results may hamper the application as an adjuvant method to oral brush biopsy-based cytology in an oral cancer surveillance program.

Management of oral leukoplakia in patients with Fanconi anemia

Fanconi anemia (FA) is a rare genetic disease involving an increased risk of developing acute myeloid leukemia and solid tumors, especially head-and-neck squamous cell carcinomas, for which the oral cavity is the most frequent site of occurrence. The patient presented in this study underwent allogeneic hematopoietic stem cell transplantation (HSCT) and developed nonhomogeneous oral leukoplakia after 7 years, which was promptly removed and diagnosed with high-grade epithelial dysplasia. Many risk conditions for oral squamous cell carcinoma were featured in the present case including FA, allogeneic HSCT, graft-versus-host disease, immunosuppressive therapy, female gender, nonsmoker, tongue location and nonhomogeneous type of leukoplakia. Close follow-up of the entire upper aerodigestive tract mucosa and early removal of all suspected lesions are highly recommended in the management of such patients.

Targeted Treatment of Head and Neck (Pre)Cancer: Preclinical Target Identification and Development of Novel Therapeutic Applications

Head and neck squamous cell carcinomas (HNSCC) develop in the mucosal lining of the upper-aerodigestive tract. In carcinogen-induced HNSCC, tumors emerge from premalignant mucosal changes characterized by tumor-associated genetic alterations, also coined as 'fields' that are occasionally visible as leukoplakia or erythroplakia lesions but are mostly invisible. Consequently, HNSCC is generally diagnosed de novo at more advanced stages in about 70% of new diagnosis. Despite intense multimodality treatment protocols, the overall 5-years survival rate is 50-60% for patients with advanced stage of disease and seems to have reached a plateau. Of notable concern is the lack of further improvement in prognosis despite advances in treatment. This can be attributed to the late clinical presentation, failure of advanced HNSCC to respond to treatment, the deficit of effective targeted therapies to eradicate tumors and precancerous changes, and the lack of suitable markers for screening and personalized therapy. The molecular landscape of head and neck cancer has been elucidated in great detail, but the absence of oncogenic mutations hampers the identification of druggable targets for therapy to improve outcome of HNSCC. Currently, functional genomic approaches are being explored to identify potential therapeutic targets. Identification and validation of essential genes for both HNSCC and oral premalignancies, accompanied with biomarkers for therapy response, are being investigated. Attentive diagnosis and targeted therapy of the preceding oral premalignant (preHNSCC) changes may prevent the development of tumors. As classic oncogene addiction through activating mutations is not a realistic concept for treatment of HNSCC, synthetic lethality and collateral lethality need to be exploited, next to immune therapies. In recent studies it was shown that cell cycle regulation and DNA damage response pathways become significantly altered in HNSCC causing replication stress, which is an avenue that deserves further exploitation as an HNSCC vulnerability for treatment. The focus of this review is to summarize the current literature on the preclinical identification of potential druggable targets for therapy of (pre)HNSCC, emerging from the variety of gene knockdown and knockout strategies, and the testing of targeted inhibitors. We will conclude with a future perspective on targeted therapy of HNSCC and premalignant changes.

Chemopreventive targeted treatment of head and neck precancer by Wee1 inhibition

HPV-negative head and neck squamous cell carcinomas (HNSCCs) develop in precancerous changes in the mucosal lining of the upper-aerodigestive tract. These precancerous cells contain cancer-associated genomic changes and cause primary tumors and local relapses. Therapeutic strategies to eradicate these precancerous cells are very limited. Using functional genomic screens, we identified the therapeutic vulnerabilities of premalignant mucosal cells, which are shared with fully malignant HNSCC cells. We screened 319 previously identified tumor-lethal siRNAs on a panel of cancer and precancerous cell lines as well as primary fibroblasts. In total we identified 147 tumor-essential genes including 34 druggable candidates. Of these 34, 13 were also essential in premalignant cells. We investigated the variable molecular basis of the vulnerabilities in tumor and premalignant cell lines and found indications of collateral lethality. Wee1-like kinase (WEE1) was amongst the most promising targets for both tumor and precancerous cells. All four precancerous cell lines were highly sensitive to Wee1 inhibition by Adavosertib (AZD1775), while primary keratinocytes tolerated this inhibitor. Wee1 inhibition caused induction of DNA damage during S-phase followed by mitotic failure in (pre)cancer cells. In conclusion, we uncovered Wee1 inhibition as a promising chemopreventive strategy for precancerous cells, with comparable responses as fully transformed HNSCC cells.

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.

Establishment and Genetic Landscape of Precancer Cell Model Systems from the Head and Neck Mucosal Lining

Head and neck squamous cell carcinomas (HNSCC) develop in fields of genetically altered cells. These fields are often dysplastic and a subset can be recognized as (erythro)leukoplakia, but most are macroscopically invisible. There is a lack of adequate treatment options to eradicate these fields, whereas they underlie the development of primary tumors as well as part of the local relapses. Unfortunately, there are almost no representative cellular models available to identify suitable treatment options. To this end, clinical biopsy specimens (n = 98) were cultured from normal appearing mucosa of the surgical margins of patients with primary HNSCCs (n = 32) to generate precancer cell culture models. This collection was extended with six previously established precancer cell cultures. Genetic analysis was performed on cultures with an extended life span (≥20 population doublings), the previously established cultures, and some randomly selected cultures. In total, cancer-associated changes were detected in 18 out of 34 (53%) cultures analyzed, which appeared to be independent of life span. A variety of genetic changes were identified, including somatic mutations as well as chromosomal copy-number aberrations (CNA). Loss of CDKN2A/p16^Ink4A and mutations in TP53/p53 were most prominent. Remarkably, in some of these precancer cell cultures only chromosomal CNAs were detected, and none of the frequently occurring driver mutations. IMPLICATIONS: The precancer cell cultures, characterized herein, form a representative collection of field models that can be exploited to identify and validate new therapeutic strategies to prevent primary HNSCCs and local relapses.

Salivary lactate dehydrogenase (LDH) as a tool for early diagnosis of oral cancer in individuals with Fanconi anemia

Currently one of the greater challenges is the diagnosis and treatment of cancer. Many studies address the genetic and metabolic aspects to support in early diagnosis and increase the survival of individuals at high risk. Individuals with Fanconi anemia can be included in this high risk group because they have a predisposition to develop head and neck cancer. The use of salivary enzymes as biomarkers to detect the changes in oral tissue at the initial phase seems viable, because saliva is easy to obtain, it moisture oral mucosa and cells metabolic compounds can be found on it. Due to the metabolic characteristics of the cancer cell, an increase in Lactate Dehydrogenase (LDH) may indicate a carcinogenesis process. The hypothesis of this study is to use of salivary LDH as a tool in the early diagnosis of oral cancer on a high risk group such as Fanconi anemia's patients.

Risk Stratification of Oral Potentially Malignant Disorders in Fanconi Anemia Patients Using Autofluorescence Imaging and Cytology-On-A Chip Assay

Fanconi anemia (FA) is a hereditary genomic instability disorder with a predisposition to leukemia and oral squamous cell carcinomas (OSCCs). Hematopoietic stem cell transplantation (HSCT) facilitates cure of bone marrow failure and leukemia and thus extends life expectancy in FA patients; however, survival of hematologic malignancies increases the risk of OSCC in these patients. We developed a "cytology-on-a-chip" (COC)-based brush biopsy assay for monitoring patients with oral potentially malignant disorders (OPMDs). Using this COC assay, we measured and correlated the cellular morphometry and Minichromosome Maintenance Complex Component 2 (MCM2) expression levels in brush biopsy samples of FA patients' OPMD with clinical risk indicators such as loss of autofluorescence (LOF), HSCT status, and mutational profiles identified by next-generation sequencing. Statistically significant differences were found in several cytology measurements based on high-risk indicators such as LOF-positive and HSCT-positive status, including greater variation in cell area and chromatin distribution, higher MCM2 expression levels, and greater numbers of white blood cells and cells with enlarged nuclei. Higher OPMD risk scores were associated with differences in the frequency of nuclear aberrations and differed based on LOF and HSCT statuses. We identified mutation of FAT1 gene in five and NOTCH-2 and TP53 genes in two cases of FA patients' OPMD. The high-risk OPMD of a non-FA patient harbored FAT1, CASP8, and TP63 mutations. Use of COC assay in combination with visualization of LOF holds promise for the early diagnosis of high-risk OPMD. These minimally invasive diagnostic tools are valuable for long-term surveillance of OSCC in FA patients and avoidance of unwarranted scalpel biopsies.

Transforming Cancer Prevention through Precision Medicine and Immune-oncology

We have entered a transformative period in cancer prevention (including early detection). Remarkable progress in precision medicine and immune-oncology, driven by extraordinary recent advances in genome-wide sequencing, big-data analytics, blood-based technologies, and deep understanding of the tumor immune microenvironment (TME), has provided unprecedented possibilities to study the biology of premalignancy. The pace of research and discovery in precision medicine and immunoprevention has been astonishing and includes the following clinical firsts reported in 2015: driver mutations detected in circulating cell-free DNA in patients with premalignant lesions (lung); clonal hematopoiesis shown to be a premalignant state; molecular selection in chemoprevention randomized controlled trial (RCT; oral); striking efficacy in RCT of combination chemoprevention targeting signaling pathway alterations mechanistically linked to germline mutation (duodenum); molecular markers for early detection validated for lung cancer and showing promise for pancreatic, liver, and ovarian cancer. Identification of HPV as the essential cause of a major global cancer burden, including HPV16 as the single driver of an epidemic of oropharyngeal cancer in men, provides unique opportunities for the dissemination and implementation of public health interventions. Important to immunoprevention beyond viral vaccines, genetic drivers of premalignant progression were associated with increasing immunosuppressive TME; and Kras vaccine efficacy in pancreas genetically engineered mouse (GEM) model required an inhibitory adjuvant (Treg depletion). In addition to developing new (e.g., epigenetic) TME regulators, recent mechanistic studies of repurposed drugs (aspirin, metformin, and tamoxifen) have identified potent immune activity. Just as precision medicine and immune-oncology are revolutionizing cancer therapy, these approaches are transforming cancer prevention. Here, we set out a brief agenda for the immediate future of cancer prevention research (including a "Pre-Cancer Genome Atlas" or "PCGA"), which will involve the inter-related fields of precision medicine and immunoprevention - pivotal elements of a broader domain of personalized public health.

Long-term Survival, Organ Function, and Malignancy after Hematopoietic Stem Cell Transplantation for Fanconi Anemia

We report on long-term survival in 157 patients with Fanconi anemia (FA) who survived 2 years or longer after their first transplantation with a median follow-up of 9 years. Marrow failure (80%) was the most common indication for transplantation. There were 20 deaths beyond 2 years after transplantation, with 12 of the deaths occurring beyond 5 years after transplantation. Donor chimerism was available for 149 patients: 112 (76%) reported > 95% chimerism, 27 (18%) reported 90% to 95% chimerism, and 8 (5%) reported 20% to 89% donor chimerism. Two patients have < 20% donor chimerism. The 10- and 15-year probabilities of survival were 90% and 79%, respectively. Results of multivariate analysis showed higher mortality risks for transplantations before 2003 (hazard ratio [HR], 7.87; P = .001), chronic graft-versus-host disease (GVHD) (HR, 3.80; P = .004) and squamous cell carcinoma after transplantation (HR, 38.17; P < .0001). The predominant cause of late mortality was squamous cell carcinoma, with an incidence of 8% and 14% at 10 and 15 years after transplantation, respectively, and was more likely to occur in those with chronic GVHD. Other causes of late mortality included chronic GVHD, infection, graft failure, other cancers, and hemorrhage. Although most patients are disease free and functional long term, our data support aggressive surveillance for long periods to identify those at risk for late mortality.