Yolanda Eby

Bio: Yolanda Eby is an academic researcher from Johns Hopkins University School of Medicine. The author has contributed to research in topics: Medicine & Antibody. The author has an hindex of 19, co-authored 28 publications receiving 4551 citations. Previous affiliations of Yolanda Eby include Johns Hopkins University.

Molecular Assessment of Histopathological Staging in Squamous-Cell Carcinoma of the Head and Neck

Abstract: Background Surgical oncologists rely heavily on the histopathological assessment of surgical margins to ensure total excision of the tumor in patients with head and neck cancer. However, current techniques may not detect small numbers of cancer cells at the margins of resection or in cervical lymph nodes. Methods We used molecular techniques to determine whether clonal populations of infiltrating tumor cells harboring mutations of the p53 gene could be detected in histopathologically negative surgical margins and cervical lymph nodes of patients with squamous-cell carcinoma of the head and neck. Results We identified 25 patients with primary squamous-cell carcinoma of the head and neck containing a p53 mutation who appeared to have had complete tumor resection on the basis of a negative histopathological assessment. In 13 of these 25 patients, molecular analysis was positive for a p53 mutation in at least one tumor margin. In 5 of 13 patients with positive margins by this method (38 percent), the carcinom...

Frequency of homozygous deletion at p16/CDKN2 in primary human tumours

Abstract: Many tumour types have been reported to have deletion of 9p21 (refs 1-6). A candidate target suppressor gene, p16 (p16INK4a/MTS-1/CDKN2), was recently identified within the commonly deleted region in tumour cell lines. An increasing and sometimes conflicting body of data has accumulated regarding the frequency of homozygous deletion and the importance of p16 in primary tumours. We tested 545 primary tumours by microsatellite analysis with existing and newly cloned markers around the p16 locus. We have now found that small homozygous deletions represent the predominant mechanism of inactivation at 9p21 in bladder tumours and are present in other tumour types, including breast and prostate cancer. Moreover, fine mapping of these deletions implicates a 170 kb minimal region that includes p16 and excludes p15.

Association between Cigarette Smoking and Mutation of the p53 Gene in Squamous-Cell Carcinoma of the Head and Neck

Abstract: Background Although epidemiologic studies have long associated tobacco and alcohol use with the development of squamous-cell carcinoma of the head and neck, the molecular targets of these carcinogens have yet to be identified. We performed a molecular analysis to determine the pattern of mutations in the p53 gene in neoplasms from patients with squamous-cell carcinoma of the head and neck and a history of tobacco or alcohol use. Methods Sequence analysis of the conserved regions of the p53 gene was performed in tumor samples from 129 patients with primary squamous-cell carcinoma of the head and neck. We then used statistical analysis to identify any patient characteristics associated with mutation of the p53 gene. Results We found p53 mutations in 42 percent of the patients (54 of 129). Fifty-eight percent of the patients who smoked cigarettes and used alcohol (37 of 64; 95 percent confidence interval, 45 to 70 percent), 33 percent of the patients who smoked but abstained from alcohol (13 of 39; 95 percen...

The Incidence of p53 Mutations Increases with Progression of Head and Neck Cancer

Abstract: To establish a genetic model of the progression of head and neck squamous carcinoma we have defined the incidence and timing of p53 mutations in this type of cancer. We sequenced the conserved regions of the p53 gene in 102 head and neck squamous carcinoma lesions. These included 65 primary invasive carcinomas and 37 noninvasive archival specimens consisting of 13 severe dysplasias and 24 carcinoma in situ lesions. The incidence of p53 mutations in noninvasive lesions was 19% (7/37) and increased to 43% (28/65) in invasive carcinomas. These data suggest that p53 mutations can precede invasion in primary head and neck cancer. Furthermore, the spectrum of codon hotspots is similar to that seen in squamous carcinoma of the lung and 64% of mutations are at G nucleotides, implicating carcinogens from tobacco smoke in the etiology of head and neck squamous carcinoma.

High Frequency of p16 (CDKN2/MTS-1/INK4A) Inactivation in Head and Neck Squamous Cell Carcinoma

Abstract: The tumor suppressor gene p16 (CDKN2/MTS-1/INK4A) can be inactivated by multiple genetic mechanisms. We analyzed 29 invasive primary head and neck squamous cell carcinomas (HNSCC) for p16 inactivation with immunohistochemistry utilizing a new monoclonal antibody (mAb), DCS-50. p16 staining of the primary lesions was correlated with genetic analysis including: (a) detailed microsatellite analysis of markers at the p16 locus to detect homozygous deletion; (b) sequence analysis of p16; and (c) Southern blot analysis to determine the methylation status of the 5' CpG island of p16. Twenty-four of 29 (83%) head and neck squamous cell carcinoma tumors displayed an absence of p16 nuclear staining using immunohistochemistry. Of these 24 tumors, we found that 16 (67%) harbored homozygous deletions, 5 (21%) were methylated, 1 displayed a rearrangement at the p16 locus, and 1 displayed a frameshift mutation in exon 1. These data suggest that: (a) inactivation of the p16 tumor suppressor gene is a frequent event in squamous cell carcinomas of the head and neck; (b) p16 is inactivated by several distinct and exclusive events including homozygous deletion, point mutation, and promoter methylation; and (c) immunohistochemical analysis for expression of the p16 gene product is an accurate and relatively simple method for evaluating p16 gene inactivation.

Human Papillomavirus and Survival of Patients with Oropharyngeal Cancer

Abstract: Background Oropharyngeal squamous-cell carcinomas caused by human papillomavirus (HPV) are associated with favorable survival, but the independent prognostic significance of tumor HPV status remains unknown. Methods We performed a retrospective analysis of the association between tumor HPV status and survival among patients with stage III or IV oropharyngeal squamous-cell carcinoma who were enrolled in a randomized trial comparing accelerated-fractionation radiotherapy (with acceleration by means of concomitant boost radiotherapy) with standard-fractionation radiotherapy, each combined with cisplatin therapy, in patients with squamous-cell carcinoma of the head and neck. Proportional-hazards models were used to compare the risk of death among patients with HPV-positive cancer and those with HPV-negative cancer. Results The median follow-up period was 4.8 years. The 3-year rate of overall survival was similar in the group receiving accelerated-fractionation radiotherapy and the group receiving standard-fractionation radiotherapy (70.3% vs. 64.3%; P = 0.18; hazard ratio for death with accelerated-fractionation radiotherapy, 0.90; 95% confidence interval [CI], 0.72 to 1.13), as were the rates of high-grade acute and late toxic events. A total of 63.8% of patients with oropharyngeal cancer (206 of 323) had HPV-positive tumors; these patients had better 3-year rates of overall survival (82.4%, vs. 57.1% among patients with HPV-negative tumors; P<0.001 by the log-rank test) and, after adjustment for age, race, tumor and nodal stage, tobacco exposure, and treatment assignment, had a 58% reduction in the risk of death (hazard ratio, 0.42; 95% CI, 0.27 to 0.66). The risk of death significantly increased with each additional packyear of tobacco smoking. Using recursive-partitioning analysis, we classified our patients as having a low, intermediate, or high risk of death on the basis of four factors: HPV status, pack-years of tobacco smoking, tumor stage, and nodal stage. Conclusions Tumor HPV status is a strong and independent prognostic factor for survival among patients with oropharyngeal cancer. (ClinicalTrials.gov number, NCT00047008.)

An Integrated Genomic Analysis of Human Glioblastoma Multiforme

Abstract: Glioblastoma multiforme (GBM) is the most common and lethal type of brain cancer. To identify the genetic alterations in GBMs, we sequenced 20,661 protein coding genes, determined the presence of amplifications and deletions using high-density oligonucleotide arrays, and performed gene expression analyses using next-generation sequencing technologies in 22 human tumor samples. This comprehensive analysis led to the discovery of a variety of genes that were not known to be altered in GBMs. Most notably, we found recurrent mutations in the active site of isocitrate dehydrogenase 1 (IDH1) in 12% of GBM patients. Mutations in IDH1 occurred in a large fraction of young patients and in most patients with secondary GBMs and were associated with an increase in overall survival. These studies demonstrate the value of unbiased genomic analyses in the characterization of human brain cancer and identify a potentially useful genetic alteration for the classification and targeted therapy of GBMs.

Oral and Maxillofacial Pathology

Abstract: 1. Developmental Defects of the Oral and Maxillofacial Region 2. Abnormalities of Teeth 3. Pulpal and Periapical Disease 4. Periodontal Diseases 5. Bacterial Infections 6. Fungal and Protozoal Diseases 7. Viral Infections 8. Physical and Chemical Injuries 9. Allergies and Immunologic Diseases 10. Epithelial Pathology 11. Salivary Gland Pathology 12. Soft Tissue Tumors 13. Hematologic Disorders 14. Bone Pathology 15. Odontogenic Cysts and Tumors 16. Dermatologic Diseases 17. Oral Manifestations of Systemic Diseases 18. Facial Pain and Neuromuscular Diseases 19. Forensic Dentistry Appendix: Differential Diagnosis of Oral and Maxillofacial Diseases Part 1: Mucosal and Soft Tissue Pathology: Color Changes Part 2: Mucosal and Soft Tissue Pathology: Surface Alterations Part 3: Mucosal and Soft Tissue Pathology: Masses or Enlargements Part 4: Radiographic Pathology Part 5: Pathology of Teeth

Evidence for a Causal Association Between Human Papillomavirus and a Subset of Head and Neck Cancers

Abstract: Background: High-risk human papillomaviruses (HPVs) are etiologic agents for anogenital tract cancers and have been detected in head and neck squamous cell carcinomas (HNSCCs). We investigated, retrospectively, an etiologic role for HPVs in a large series of patients with HNSCC. Methods: Tumor tissues from 253 patients with newly diagnosed or recurrent HNSCC were tested for the presence of HPV genome by use of polymerase chain reaction (PCR)-based assays, Southern blot hybridization, and in situ hybridization. The viral E6 coding region was sequenced to confirm the presence of tumor-specific viral isolates. Exons 5‐9 of the TP53 gene were sequenced from 166 specimens. The hazard of death from HNSCC in patients with and without HPVpositive tumors was determined by proportional hazards regression analysis. Results: HPV was detected in 62 (25%) of 253 cases (95% confidence interval [CI] = 19%‐30%). Highrisk, tumorigenic type HPV16 was identified in 90% of the HPV-positive tumors. HPV16 was localized specifically by in situ hybridization within the nuclei of cancer cells in preinvasive, invasive, and lymph node disease. Southern blot hybridization patterns were consistent with viral integration. Poor tumor grade (odds ratio [OR] = 2.4; 95% CI = 1.2‐ 4.9) and oropharyngeal site (OR = 6.2; 95% CI = 3.1‐12.1) independently increased the probability of HPV presence. As compared with HPV-negative oropharyngeal cancers, HPVpositive oropharyngeal cancers were less likely to occur among moderate to heavy drinkers (OR = 0.17; 95% CI = 0.05‐0.61) and smokers (OR = 0.16; 95% CI = 0.02‐1.4), had a characteristic basaloid morphology (OR = 18.7; 95% CI = 2.1‐167), were less likely to have TP53 mutations (OR = 0.06; 95% CI = 0.01‐0.36), and had improved disease-specific survival (hazard ratio [HR] = 0.26; 95% CI = 0.07‐0.98). After adjustment for the presence of lymph node disease (HR = 2.3; 95% CI = 1.4‐ 3.8), heavy alcohol consumption (HR = 2.6; 95% CI = 1.4‐4.7), and age greater than 60 years old (HR = 1.4; 95% CI = 0.8‐2.3), all patients with HPV-positive tumors had a 59% reduction in risk of death from cancer when compared with HPV-negative HNSCC patients (HR = 0.41; 95% CI = 0.20‐0.88). Conclusions: These data extend recent molecular and epidemiologic studies and strongly suggest that HPV-positive oropharyngeal cancers comprise a distinct molecular, clinical, and pathologic disease entity that is likely causally associated with HPV infection and that has a markedly improved prognosis. [J Natl Cancer Inst 2000; 92:709‐20]

Cell cycle control and cancer

Abstract: Multiple genetic changes occur during the evolution of normal cells into cancer cells. This evolution is facilitated in cancer cells by loss of fidelity in the processes that replicate, repair, and segregate the genome. Recent advances in our understanding of the cell cycle reveal how fidelity is normally achieved by the coordinated activity of cyclin-dependent kinases, checkpoint controls, and repair pathways and how this fidelity can be abrogated by specific genetic changes. These insights suggest molecular mechanisms for cellular transformation and may help to identify potential targets for improved cancer therapies.