The loss of heterozygosity in retinoblastoma and p53 suppressor genes as a prognostic indicator for head and neck cancer

Head and Neck Squamous Cell Carcinoma: Epigenetic Landscape

Head and neck squamous carcinoma (HNSCC) constitutes the sixth most prevalent cancer worldwide. The molecular pathogenesis of HNSCC includes disorders in cell cycle, intercellular signaling, proliferation, squamous cell differentiation and apoptosis. In addition to the genetic mutations, changes in HNSCC are also characterized by the accumulation of epigenetic alterations such as DNA methylation, histone modifications, non-coding RNA activity and RNA methylation. In fact, some of them may promote cancer formation and progression by controlling the gene expression machinery, hence, they could be used as biomarkers in the clinical surveillance of HNSCC or as targets for therapeutic strategies. In this review, we focus on the current knowledge regarding epigenetic modifications observed in HNSCC and its predictive value for cancer development.

Expression of Cell Cycle-associated Proteins p53, pRb, p16, p27, and Correlation With Survival: A Comparative Study on Oral Squamous Cell Carcinoma and Verrucous Carcinoma

Verrucous carcinoma (VC) is a well-differentiated form of squamous cell carcinoma (SCC) with better prognosis. Differences in molecular pathogenesis between the 2 have not been well-characterized. We conducted this study to evaluate immunohistochemical expression of cell-cycle regulatory proteins p53, pRb, p16, and p27 in SCC and VC, compare the expression in these 2 neoplasms, and assess if these markers have any diagnostic or prognostic value. Sixty cases of SCC with and without lymph node metastasis and 31 cases of VC were studied. Immunohistochemical analysis for p53, pRb, p16, and p27 was performed and the results were analyzed. SCC was most frequent in tongue (52%), whereas VC in buccal mucosa (81%). Mean age of SCC patients was significantly lower than in VC. Majority of SCCs were in stage III and IV (63%), whereas VCs were in stage I and II (84%). p53 immunopositivity was more frequent in SCC (65%) than in VC (23%) (P≤0.001). VC had lower p53 as compared with well-differentiated SCC and SCC without lymph node metastasis. No significant difference was seen in pRb, p16, and p27 expression. Disease-free survival (DFS) at 1 year for SCC was 57% whereas it was 80% for VC (P=0.02). DFS and overall survival of SCC correlated with nodal status and stage; cell-cycle-associated protein expression had no association with DFS. To conclude, p53 immunoexpression differs in SCC and VC, suggesting different pathogenesis, and it may have some utility as an adjunct to morphology to differentiate between the 2. Expression of cell-cycle-associated proteins does not influence survival in SCC.

Loss of heterozygosity in mammary serine protease inhibitor (maspin) and p53 at chromosome 17 and 18 in oral cavity squamous cell carcinoma

BACKGROUND

The purpose of this study was to evaluate the loss of heterozygosity (LOH) in chromosomes 17p13 (p53 gene) and in 18q21 (mammary serine protease inhibitor [maspin] gene), and the expression of both genes in tissues, in patients with oral cavity squamous cell carcinoma (SCC).

METHODS

Thirty patients with oral cavity SCC have been evaluated for the presence of LOH in chromosomes 17p13 and 18q21, and the expression of p53 and maspin in tissues. Clinicopathological features and survival in these patients were also analyzed.

RESULTS

LOH in 17p13 was more frequently identified in patients with lymph node metastasis and/or high TNM classification. LOH in 18q21 was more frequently identified in high primary T classification patients. Increased expression rate of p53 and/or decreased maspin expression rate were significantly higher in oral cavity SCC than normal tissues.

CONCLUSION

LOH on chromosome 17, 18, the expression of p53, and maspin are related to the carcinogenesis of oral cavity SCC. Relationships with clinicopathological factors in oral cavity SCC were also revealed. © 2014 Wiley Periodicals, Inc. Head Neck 37: 1239-1245, 2015.

DNA copy number variation and loss of heterozygosity in relation to recurrence of and survival from head and neck squamous cell carcinoma: a review

Genetic aberrations, such as DNA copy number variation (CNV) and loss of heterozygosity (LOH), have been implicated in head and neck squamous cell carcinoma (HNSCC) initiation and progression. This review examines CNV and LOH as predictors of HNSCC recurrence and mortality. We searched PubMed for relevant publications and compared and discussed results from the articles. Certain CNV and LOH events have consistently been associated with HNSCC recurrence and survival. The recent high-resolution single nucleotide polymorphism (SNP) arrays have the potential to identify many more genetic changes and concurrent genome-wide CNV, copy-neutral and/or allelic imbalance LOH in HNSCC that may bear on prognosis. Our review confirms that outcome in HNSCC can be predicted to a considerable extent by the presence of tumor cell genetic aberrations. It points out the limitations of some methodologies that were used in the past and discusses the advantages and challenges of using genome-wide SNP arrays.

The Calcium-binding Protein S100A2 Interacts with p53 and Modulates Its Transcriptional Activity

Head and neck squamous cell carcinoma express high levels of the EF-hand calcium-binding protein S100A2 in contrast to other tumorigenic tissues and cell lines where the expression of this protein is reduced. Subtractive hybridization of tumorigenic versus normal tumor-derived mammary epithelial cells has previously identified the S100A2 protein as potential tumor suppressor. The biological function of S100A2 in carcinogenesis, however, has not been elucidated to date. Here, we report for the first time that during recovery from hydroxyurea treatment, the S100A2 protein translocated from the cytoplasm to the nucleus and co-localized with the tumor suppressor p53 in two different oral carcinoma cells (FADU and SCC-25). Co-immunoprecipitation experiments and electrophoretic mobility shift assay showed that the interaction between S100A2 and p53 is Ca(2+)-dependent. Preliminary characterization of this interaction indicated that the region in p53 involved with binding to S100A2 is located at the C terminus of p53. Finally, luciferase-coupled transactivation assays, where a p53-reporter construct was used, indicated that interaction with S100A2 increased p53 transcriptional activity. Our data suggest that in oral cancer cells the Ca(2+)- and cell cycle-dependent p53-S100A2 interaction might modulate proliferation.

Frequent allelic loss of 21q11.1∼q21.1 region in advanced stage oral squamous cell carcinoma

A fine mapping of loss of heterozygosity (LOH) was performed in oral squamous cell carcinoma (OSCC), using 12 markers on 21q11.1 approximately q21.1. We studied 43 resected primary invasive tumors and their paired normal tissues, concurrent dysplasia or carcinoma in situ in separate areas from 8 of the specimens, and 6 local recurrent carcinomas. LOH status was compared between lesions of different phases of progression within the same patient. A high frequency of LOH was observed for D21S1410, D21S120, and D21S1433 (60% each) in the primary lesions, constituting two interstitial deleted regions encompassing eight known genes. Cases showing LOH of D21S120 were significantly associated with advanced clinical stages (III and IV; P=0.02). Consistent allelic loss was observed in 64.2% of the informative cases between the precursor lesions and their corresponding invasive tumors, and in 59.5% of those between the primary lesions and their recurrent counterparts. Fewer than half of the different lesions within a given patient showed discordant allelic loss for tested markers. Our results suggest that 21q11.1 approximately q21.1 harbors tumor suppressor genes in OSCC. Genetic divergence may develop during tumor clone evolution.

p53 Codon 72 Polymorphic Variants, Loss of Allele-Specific Transcription, and Human Papilloma Virus 16 and/or 18 E6 Messenger RNA Expression in Squamous Cell Carcinomas of the Head and Neck

A polymorphism at codon 72 of the human tumor suppressor p53 determines translation into either arginine or proline. Yet, the impact of this amino acid variability on the risk to develop malignant tumors, particularly carcinomas associated with human papilloma virus (HPV) infections, remains unresolved because of contradictory results. To address a potential correlation between the different genotypes and the manifestation of squamous cell carcinomas of the head and neck (SCCHN), we determined the p53 codon 72 in 193 healthy subjects and 122 unselected SCCHN with known HPV status. Furthermore, loss of allele-specific transcription was analyzed in p53 codon 72 heterozygous (Arg/Pro) SCCHN and correlated with HPV 16 and/or 18 E6 transcript expression. We found a moderately increased risk (odds ratio, 1.86; 95% confidence interval, 1.0-3.3) for individuals with germ line heterozygosity to develop SCC of the pharynx. On the other hand, p53 codon 72 polymorphic variants, most notably the Arg/Arg genotype, showed no association with the presence of HPV 16 and/or 18 E6 transcript. Moreover, there was no evidence for HPV-driven selection in SCCHN with allele-specific loss of transcription. Our data suggest that the p53 codon 72 polymorphism has a minor impact on the development of SCCHN.

Prognostic and predictive factors in oral squamous cell cancer: important tools for planning individual therapy?

An escalation in the incidence of oral cancer and its attributable mortality has been observed in recent decades in Europe; oral cancer is expected to become a public health problem in the foreseeable future. However, survival rates have remained at a disappointingly stable level despite significant development in the multimodality treatment of the disease. Additionally, due to the limited prognostic value of conventional prognostic factors and the uniformity of treatment strategies, several patients are still over- or under-treated with significant personal and socio-economical impact. Here we review some promising prognostic and predictive markers that can help the clinician to improve prognostic accuracy and define the most appropriate management for the individual patient with oral cancer.

Evidence of p53 immunohistochemical overexpression in ethmoidal mucosa of woodworkers

A high risk of neoplastic transformation of nasal and paranasal sinuses mucosa is related to the occupational exposure to wood dust, however no conclusive data have been reported up to now about morphological precursors of these tumors, mechanisms of carcinogenesis and role of p53 gene. Immunohistochemical overexpression of protein p53 (DO7 clone) by epithelial cells of ethmoidal mucosa was investigated on 60 woodworkers occupationally exposed for a minimum of 10 years, on 50 functional and/or esthetic nasal surgery patients (control group) and on 15 cases of intestinal-type adenocarcinoma, 10 of these involving subjects who had a longtime exposure to wood dust. In almost all the woodworkers (92%) the normal ciliated epithelium showed tracts of squamous metaplasia. The mean percentage of p53-positive cells in woodworkers and in controls was 28.6 and 7.97%, respectively, in metaplastic epithelium (P<0.001), 11.7 and 2.08% in ciliated epithelium (P<0.001), 12.46 and 1.03% (P<0.001) in the sero-mucous glands of the nasal stroma. Both in tracts of metaplastic epithelium and in those of ciliated epithelium, positive cells were distributed in basal and suprabasal layers. A high number of p53-positive cells was also observed in the normal ciliated epithelium close to the neoplastic cells, of intestinal-type adenocarcinomas affecting subjects with longtime exposure to wood dust. Moreover, a higher number of p53 positive neoplastic cells was showed by the cases occurring in occupationally exposed patients than by the others. The following conclusions can be drawn: (1) in the ethmoidal mucosa, a region at high risk of carcinogenesis in subjects exposed to wood dust, epithelial cells overexpress p53 protein, and this may be linked to the presence of p53 gene mutations; malignant transformation, as at other head and neck sites, may thus occur through this pathway; (2) the presence of p53 overexpression in sero-mucous glands is in keeping with the histogenesis of some tumors from these structures; (3) since tumors of nose and paranasal sinuses, mainly adenocarcinoma, are recognized as occupational neoplasias, immunohistochemical evaluation of p53, perhaps combined with molecular methods, could be the first step to detect subjects at high risk of carcinogenesis among woodworkers.

Clinical significance of allelotype profiling for urothelial carcinoma

OBJECTIVES

To perform a global loss of heterozygosity (LOH) analysis on a cohort of urothelial carcinoma to investigate the clinical implication of specific chromosomal loss. Allelic deletions detected as LOH have been used to study the markers for carcinogenesis.

METHODS

We examined the allelic loss on 14 chromosomal regions in a total of 71 cases of urothelial carcinoma. The results were analyzed in relation to biologic indicators of urothelial carcinoma and the clinical outcome with a mean follow-up of 101 months.

RESULTS

The incidence of LOH in order of frequency was 9p (54.9%), 9q (49.3%), 13q (40.8%), 14q (40.8%), 10q (39.4%), 17p (39.4%), 8p (38.0%), 21q (36.6%), 11p (31.0%), 18q (23.9%), 4q (21.1%), 3p (16.9%), 6q (14.1%), and 1q (8.5%). Positive association with one of the indicators was observed in 3p, 9p, 9q, 10q, 14q, and 18q. The chromosomes that correlated with two biologic indicators were 4q, 6q, 11p, 17p, and 21q. Univariate analysis found that patients having combined 9p and 14q deleted tumors had particularly poor long-term survival compared with those with other patterns of chromosomal alterations (P = 0.01). In the multivariate model, nonpapillary tumors had a greater risk of recurrence, and stage classification was the only important indicator in predicting patient survival (P = 0.04).

CONCLUSIONS

LOH assessment does not provide independent prognostic value compared with stage classification. However, chromosomes 4q, 6q, 9p, 11p, 14q, 17p, and 21q may harbor important tumor suppressor genes involved in the progression of urothelial carcinogenesis.

[Genic alterations in oral and head and neck squamous cell carcinomas: analysis of international literature]

The development of oral and head and neck squamous cell carcinomas occurs in relation with multiple events including mainly: loss of cycle cell control, evasion from apoptosis, telomerase reactivation. Complex interactions between a set of molecules, cell cycle proteins, tumour suppressor genes, oncogenes and the telomerase, occur in the multiple step process of carcinogenesis. The 2 main ways of control of the cell cycle rely on 2 tumour suppressor genes: the P53 gene and the retinoblastoma gene or RB gene. One of the regulation pathways or the 2 regulation pathways are disabled during the development of oral and head and neck squamous cell carcinomas. Most of the time, the inactivation of the P53 pathway results from a loss of function of the p53 protein, secondary to mutation and/or deletion of the P53 gene; It may also result of the amplification of the MDM2 gene and of the inactivation of the arf protein. The RB pathway leads to cell proliferation by loss of the p16 protein, by amplification of the cyclin D1 gene and less frequently by mutation of the RB gene or loss of the retinoblastoma protein. In India and South-East Asia, the activation of RAS and MYC oncogenes appears to be related with the presence of specific carcinogens in snuff and tobacco. By blocking apoptosis, the Bcl2 protein seems to increase the resistance of tumours to radiotherapy and chemotherapy.

Helicobacter pylori infection generated gastric cancer through p53-Rb tumor-suppressor system mutation and telomerase reactivation

AIM

To investigate the relationship between Helicobacter pylori (H.pylori) infection and the expressions of the p53, Rb, c-myc, bcl-2 and hTERT mRNA in a series of diseases from chronic gastritis (CG), intestinal metaplasia type I or II(IMI-II), intestinal metaplasia type III (IMIII), mild or modest dysplasia (DysI-II), severe dysplasia (DysIII) to gastric cancer(GC) and to elucidate the mechanism of gastric carcinogenesis relating to H.pylori infection.

METHODS

272 cases between 1998 and 2001 were available for the study including 42 cases of CG, 46 cases of IMI-II, 25 cases of IMIII, 48 cases of DysI-II, 27 cases of DysIII, 84 cases of GC. H.pylori infection and the expressions of p53, Rb, c-myc, bcl-2 were detected by means of streptavidin-peroxidase (SP) immunohistochemical method. HTERT mRNA was detected by in situ hybridization (ISH).

RESULTS

The expressions of p53, Rb, c-myc, hTERT mRNA and bcl-2 were higher in the GC than in CG, IM, Dys. The expression of c-myc was higher in IMIII with H.pylori infection (10/16) than that without infection (1/9) and the positive rate in DysI-II and DysIII with H.pylori infection was 18/30 and 13/17, respectively, higher than that without infection (4/18 and 3/10, respectively). In our experiment mutated p53 had no association with H.pylori infection, the expression of Rb was associated with H.pylori infection in GC, but the p53-Rb tumor-suppressor system abnormal in DysI-II cases, DysIII and GC cases with H.pylori infection was 21/30, 15/17 and 48/48 respectively, higher than non-infection groups (4/18, 3/10, 28/36). Furthermore the level of hTERT mRNA in GC with H.pylori infection (47/48) was higher than that without infection (30/36), however the relationship between bcl-2 and H.pylori was only in IMIII. C-myc had a close association with hTERT mRNA in DysIII and GC (P=0.0 253,0.0 305 respectively).

CONCLUSION

In the gastric carcinogenesis, H.pylori might cause the severe imbalance of proliferation and apoptosis in the precancerous lesions (IMIII and GysIII) first, leading to p53-Rb tumor-suppressor system mutation and telomerase reactivation, and finally causes gastric cancer.

Molecular genetics of head and neck cancer

BACKGROUND

Head and neck cancers have multiple genetic abnormalities that influence tumor behavior and may be useful in developing new treatments.

METHODS

Genetic alterations implicated in head and neck cancer oncogenesis and behavior are reviewed, and molecular techniques for detection and treatment are evaluated.

RESULTS

The large number of genetic changes present in head and neck cancer cells precludes meaningful use of simple molecular tests and treatments. Detection of abnormalities in multiple genes provides better prognostic information than the detection and assessment of single mutations. Screening tests that rely on amplification of genetic material present in bodily fluids are hindered by the genomic complexity of head and neck cancer. Introduction of genetic material into head and neck cancer cells for gene therapy has shown some efficacy.

CONCLUSIONS

Head and neck cancers comprise a complex genetic disease. Although much has been learned about the molecular genetics of head and neck cancers, continued study of multiple genes is critical for further progress. Gene therapy, although promising, must also overcome this complexity.

Genetic alterations in squamous cell carcinomas of the hypopharynx with correlations to clinicopathological features

The objective of this study is to describe the molecular alterations in carcinomas in one specific location of the head and neck, the hypopharynx. Thirty-seven hypopharyngeal squamous cell carcinomas were studied. The DNA from tumour and healthy tissue was evaluated for amplification of the 11q13 region and of the MYC and ERBB1 oncogenes, for integration of the Human Papillomavirus (HPV), and for loss of heterozygosity (LOH) at p53 and NAT2 loci. The most common alteration was the amplification of the 11q13 region (78% of the cases), followed by LOH at p53 locus (70%). MYC amplification was found in 19% of the cases, ERBB1 amplification in 29%, LOH at NAT2 locus in 25%, and integration of the HPV in 29%. 11q13 amplification was related with nodal metastases and higher tumour recurrence rates. These findings confirm that 11q13 amplification is one of the most frequent genetic alterations in hypopharyngeal squamous cell carcinomas, and that it may have prognostic significance in these tumours.

Clonality of combined tumors

CONTEXT

Tumors with mixed morphologic patterns (combined tumors) are sometimes encountered, and questions often arise regarding the mechanism of molecular pathogenesis of each component and their relationships.

OBJECTIVE

To determine whether different components of combined tumors contain the same or different genetic alterations, thus providing evidence for their clonality.

MATERIALS AND METHODS

Six combined tumors with 2 components (in each case, both components showed epithelial differentiation morphologically) were studied by microdissecting tumor cells from each morphologic area followed by loss of heterozygosity analysis.

RESULTS

In 1 of the cases studied, the different morphologic areas contained different patterns of genetic alterations. In the remaining 5 cases, the different morphologic areas harbored identical genetic changes in the chromosome regions studied. The latter group, interestingly, included a colonic tumor with an area of tubulovillous adenoma and an area of neuroendocrine carcinoma, and 2 lung tumors with squamous carcinoma and small cell carcinoma components.

CONCLUSIONS

Our results suggest that in the majority of combined tumors, cells with different phenotypes share similar genotype and may arise from a single precursor cell. However, in a minority of these tumors, different areas may be derived from different precursor cells.

[Inactivation of p53 and amplification of cyclin D1 in squamous cell carcinomas of the head and neck]

P53 and CCND1 (cyclin D1) genes play a critical role in the cell cycle regulation. Abnormalities of these genes are frequent in different types of cancers, including those of the head and neck. The aim of this work is to investigate whether P53 inactivation (determined by loss of heterozygosity analysis) is related to CCND1 gene amplification (determined by differential PCR analysis), and if these alterations are correlated with clinical outcome in a series of 56 patients with squamous cell carcinoma of the head and neck. Loss of heterozygosity of the P53 gene was found in 39 cases (70%) and CCND1 amplification in 17 cases (30%). Both abnormalities together were found in 11 cases (20%), without a significant association between them (P = 0.83). No relationship was found between P53 inactivation, the clinico-pathological parameters analyzed and the clinical outcome. CCND1 amplification was associated with advanced T-stages (P = 0.02), nodal metastases (P = 0.01) and a decreased survival (P = 0.002). The combination of both abnormalities shows a pattern that seems to be additive, since it was associated with an increase in tumor recurrences and a decrease in survival that was higher than for either of them individually. In conclusion, P53 and CCND1 abnormalities are frequent in squamous cell carcinomas of the head and neck. The combined analysis of these abnormalities seems to be more informative than either of them individually and may have a prognostic value in these carcinomas.

[Relationship between the integration of human papillomavirus and loss of heterozygosity of the P53 gene in squamous cell carcinomas of the head and neck]

Human papillomavirus integration in cellular DNA and loss of heterozygosity of P53 gene are both related with tumour formation process by promoting genomic instability that leads to DNA abnormalities accumulation. In order to analyze the relationship between both events, 26 squamous cell carcinomas of the head and neck were studied. HPV 16 and 6b DNA was detected by PCR in 8 cases (31%), whereas P53 loss of heterozygosity was present in 16 cases (61%). No correlation was found between both events and they were not related to clinical factors neither the prognosis. Consequently, HPV integration and loss of heterozygosity of P53 seem to act independently in the genesis of these tumours.

Variability of genetic alterations in different sites of head and neck cancer

OBJECTIVE

Tumors arising from different sites of the head and neck area have different clinical behavior. However, most of the studies on genetic alterations in head and neck squamous cell carcinomas do not make a distinction between the sites within this area. The objective of this study is to compare the genetic alterations in three different sites of the head and neck (larynx, oropharynx, and hypopharynx).

STUDY DESIGN

Prospective study.

METHODS

Thirty-eight laryngeal, 29 oropharyngeal, and 37 hypopharyngeal carcinomas were studied. DNA from tumor and healthy tissue was evaluated for amplification of the oncogenes at 11q13 region (CCND1, FGF3, FGF4 and EMS1) and of the oncogenes MYC and ERBB1; for integration of the human papillomavirus (HPV) types 6b and 16; for loss of heterozygosity (LOH) at p53 and NAT2; and for the cellular DNA content.

RESULTS

FGF3 and FGF4 showed a significantly higher frequency of amplification in hypopharyngeal tumors (P =.006 and P =.0002, respectively). CCND1 amplification had a nearly statistically significant (P =.072) higher frequency of amplification in hypopharyngeal tumors. Aneuploid tumors were found in a significantly lower proportion in the larynx (P =.03) compared with the other sites. For the other genetic alterations, no significant differences among the three sites were found.

CONCLUSIONS

These results suggest that cancers originating from different sites in the head and neck may have different tumor biology. Therefore, they should be considered as different entities.

[Molecular changes in epidermoid carcinoma of the oropharynx]

In most of the studies about molecular alterations in squamous cell carcinomas of the head and neck there is not distinction between the different subsites of this area. The objective of this study is to describe the molecular alterations in squamous cell carcinomas of the oropharynx. Twenty-nine oropharyngeal carcinomas, with a minimum follow-up of 36 months, were studied. The molecular alterations analyzed were: the amplification of 11q13 region (in the 29 cases), and the MYC and ERBB1 oncogenes (in 22 cases); the integration of Human Papillomavirus (HPV) types 6b and 16 (in 22 cases); the loss of heterozygosity (LOH) of p53 and N-acetyltransferase-2 (NAT2) gene (in 12 and 13 informative cases, respectively); and the cellular DNA content (in 13 cases). The most frequent alterations found were the LOH at p53 (67%), and NAT2 (54%) locus, followed by 11q13 amplification (49%). ERBB1 amplification was found in 14% of the cases, and MYC amplification only in one (5%). Integration of the HPV was found in 23% of the cases. Nine (69%) of the 13 analyzed cases were aneuploid. The only alteration with a prognostic significance was 11q13 amplification that showed a tendency to be associated with a higher frequency of nodal metastases and tumor recurrence.

Gene therapy for head and neck cancer

OBJECTIVES/HYPOTHESIS

New treatment methods are needed for head and neck cancer to improve survival without increasing morbidity. Gene therapy is a potential method of improving patient outcome. Progress in gene therapy for cancer is reviewed with emphasis on the limitations of vector technology and treatment strategies. Given the current technological vector limitations in transmitting the therapeutic genes, treatments that require the fewest number of cells to be altered by the new gene are optimal. Therefore an immune-based gene therapy strategy was selected in which the tumors were transfected with the gene for an alloantigen, human leukocyte antigen (HLA)-B7, a class I major histocompatibility complex (MHC). This would restore an antigen presentation mechanism in the tumor to induce an antitumor response. This gene therapy strategy was tested in patients with advanced, unresectable head and neck cancer.

STUDY DESIGN

Prospective trial.

METHODS

Twenty patients with advanced head and neck cancer who had failed conventional therapy and did not express HLA-B7 were treated with gene therapy using a lipid vector by direct intratumoral injection. The gene therapy product contained the HLA-B7 gene and the beta2-microglobulin gene, which permits complete expression of the class I MHC at the cell surface. Patients were assessed for any adverse effects, for changes in tumor size, for time to disease progression, and for survival. Biopsy specimens were assessed for pathological response, HLA-B7 expression, apoptosis, cellular proliferation, CD-8 cells, granzyme, and p53 status.

RESULTS

There were no adverse effects from the gene therapy. At 16 weeks after beginning gene therapy, four patients had a partial response and two patients had stable disease. Two of the tumors completely responded clinically, but tumor was still seen on pathological examination. The time to disease progression in the responding patients was 20 to 80 weeks. The median survival in patients who completed gene therapy was 54 weeks, compared with 21 weeks in patients whose tumors progressed after the first cycle of treatment. One patient survived for 106 weeks without any additional therapy. HLA-B7 was demonstrated in the treated tumors, and increased apoptosis was seen in the responding tumors.

CONCLUSION

Significant advances have been made in the field of gene therapy for cancer. Alloantigen gene therapy has had efficacy in the treatment of cancer and can induce tumor responses in head and neck tumors. Alloantigen gene therapy has significant potential as an adjunctive treatment of head and neck cancer.

DNA alterations in tumor scrapes vs. biopsies of squamous-cell carcinomas of the head and neck

Genetic abnormalities in SCCHNs are frequent and may be useful for screening, follow-up and prognosis. A biopsy or resection generally is utilized to identify these alterations but analysis of scraped or exfoliated tumor cells has been proposed as simpler and more versatile. It is unknown how well genetic abnormalities in scrapes reflect those in the tumor. Therefore, we compared DNA alterations in tumor scrapes obtained prior to treatment with alterations in microdissected tumor biopsies. Eight primary squamous-cell carcinomas of the head and neck (SCCHNs) were examined at 14 loci to determine loss of heterozygosity (LOH) at sites on 3p, 9p, 11p, 11q and 17p and amplification of cyclin D1 (CCND1). All biopsies contained DNA alterations, but only 3/8 scrapes contained unequivocal abnormalities; 4/8 contained subtle alterations that could not have been definitively identified without comparison to the paired biopsies. Overall, 22 alterations were detected in the biopsies: 8/22 were found unequivocally in the scrapes; 7/22 were identifiable in scrapes only after the biopsy alterations were defined and 7/22 were absent from scrapes. One LOH in scrape, but not biopsy, DNA was found. Discrepancies between scrapes and tumors tended to increase if multiple tumor samples were examined. We conclude that DNA alterations can be detected in scrapes of SCCHNs but may inaccurately reflect the tumor's complex genetic abnormalities. This may be due to contamination of scrapes with normal cells or to genetic heterogeneity within the tumor not represented in the scrape. Although examining scrapes of SCCHNs is an attractive technique, its clinical utility may have limitations.

Molecular markers as prognostic factors for local recurrence and radioresistance in head and neck squamous cell carcinoma

Squamous cell carcinoma of the head and neck affects more than 500,000 people worldwide each year. Local-regional recurrence of disease is a common and challenging oncological problem in patients affected by this disease. Identification of risk factors for local relapse after appropriate local therapy with surgery, radiation, or combination therapy remains an active area of clinical research. The recent development of novel molecular markers has resulted in numerous studies evaluating the prognostic significance and potential clinical utility of these markers in identifying patients at risk for local-regional relapse. This article reviews recent studies evaluating molecular markers, including p53, angiogenesis-related markers, cyclin D1, epidermal growth factor receptor, loss of heterozygosity, DNA ploidy, and cell kinetic markers. The potential clinical utility of these markers and future directions along this avenue of investigation are discussed.

Centrosome hyperamplification in human cancer: chromosome instability induced by p53 mutation and/or Mdm2 overexpression

We have previously reported that loss of p53 tumor suppressor protein results in centrosome hyperamplification, which leads to aberrant mitosis and chromosome instability. Since p53 is either deleted or mutated in human cancers at a high frequency, we investigated whether human cancers showed centrosome hyperamplification. Screening of advanced stage breast ductal carcinomas and squamous cell carcinomas of the head and neck (SCCHN) revealed that centrosome hyperamplification is frequent in both tumor types. Moreover, through the analyses of p53 in SCCHN samples by direct sequencing and by loss-of-heterozygosity test, we found that p53 mutations correlated with occurrence of centrosome hyperamplification. However, in some cases, we observed centrosome hyperamplification in tumors that retained wild-type p53. These tumors contained high levels of Mdm2. Since Mdm2 can inactivate p53 through physical association, we investigated whether Mdm2 overexpression induced centrosome hyperamplification. We found that Mdm2 overexpression, like loss of p53, induced centrosome hyperamplification and chromosome instability in cultured cells.