Patterns of chromosomal aberrations in metastasizing and nonmetastasizing squamous cell carcinomas of the oropharynx and hypopharynx

Understanding Keloid Pathobiology From a Quasi-Neoplastic Perspective: Less of a Scar and More of a Chronic Inflammatory Disease With Cancer-Like Tendencies

Keloids are considered as benign fibroproliferative skin tumors growing beyond the site of the original dermal injury. Although traditionally viewed as a form of skin scarring, keloids display many cancer-like characteristics such as progressive uncontrolled growth, lack of spontaneous regression and extremely high rates of recurrence. Phenotypically, keloids are consistent with non-malignant dermal tumors that are due to the excessive overproduction of collagen which never metastasize. Within the remit of keloid pathobiology, there is increasing evidence for the various interplay of neoplastic-promoting and suppressing factors, which may explain its aggressive clinical behavior. Amongst the most compelling parallels between keloids and cancer are their shared cellular bioenergetics, epigenetic methylation profiles and epithelial-to-mesenchymal transition amongst other disease biological (genotypic and phenotypic) behaviors. This review explores the quasi-neoplastic or cancer-like properties of keloids and highlights areas for future study.

Oral field cancerization: an update on current concepts

There always exists a field with genetically altered cells with a high risk of developing premalignant and malignant lesions. It may often happen that an individual stem cell is genetically altered and can cause the formation of a clone or a patch which is likely to turn into a tumor. This explains the higher recurrence rates following tumor resections. It is essential to identify and to treat this field in order to have greater chances to prevent cancer and achieve a better outcome. This article reports concepts, theories and markers for the assessment of field cancerization.

Identification of proteomic differences between squamous cell carcinoma of the lung and bronchial epithelium

Proteins that exhibit different expression levels in normal and malignant lung cells are good candidate biomarkers to improve early diagnosis and intervention. We used a quantitative approach and compared the proteome of microdissected cells from normal human bronchial epithelium and squamous cell carcinoma tumors of histopathological grades G2 and G3. DIGE analysis and subsequent MS-based protein identification revealed that 32 non-redundant proteins were differentially regulated between the respective tissue types. These proteins are mainly involved in energy pathways, cell growth or maintenance mechanisms, protein metabolism, and the regulation of DNA and RNA metabolism. The expression of some of these proteins was analyzed by immunohistochemistry using tissue microarrays containing tissue specimen of 55 patients, including normal bronchial epithelium, squamous cell carcinomas, adenocarcinomas, and large cell carcinomas. The results of the immunohistochemical studies correlated with the proteome study data and revealed that particularly HSP47 and a group of cytokeratins (i.e. cytokeratins 6a, 16, and 17) are significantly co-regulated in squamous cell carcinoma. Furthermore cytokeratin 17 showed significantly higher abundance in G2 grade compared with G3 grade squamous cell carcinomas in both the gel-based and the immunohistochemical analysis. Therefore this protein might be used as a marker for stratification between different tumor grades.

Genetic differences between primary larynx and pharynx carcinomas and their matched lymph node metastases by multiplex ligation-dependent probe amplification

Lymph nodes metastasis is a major risk factor related to poor survival in larynx and pharynx carcinomas. The aim of this study is to search for markers of lymph node involvement analyzing the genetic differences between primary larynx and pharynx squamous cell carcinomas and their corresponding lymph node metastases. Twenty-five primary tumors and their corresponding lymph node metastases were examined. DNA copy number changes of 37 genes were analyzed by multiplex ligation-dependent probe amplification (MLPA). Loss of CDKN2A (9p21) occurred in 14 out of 25 pairs (56%) of primary tumor and lymph node metastases. Loss of LMNA (1q21) was exclusively detected in 8 lymph node samples (32%). Loss of CTNNB1 (3p22) and gain of CDKN2D (19p13) were also significantly more frequent in lymph node metastases. Other aberrations related to lymph node metastases were loss of MFHAS1 (8p23), RECQL4 (8q24) and gain of N33 (8p22) and TP53 (17p13). Primary tumor and corresponding lymph node metastases showed common genetic changes. However, the lymph node metastases presented with a number of additional alterations. Acquisition of these alterations may play a role in lymphatic metastasis development.

Unraveling the chromosomal aberrations of head and neck squamous cell carcinoma: a review

Information from the genetic analysis of head and neck cancer has grown enormously in the last 20 years. The advent of high-resolution genetic analysis techniques such as microarray technology will further expand this field in the future. Here we review the data on chromosomal aberrations of head and neck squamous cell carcinoma, focusing on the data generated by comparative genomic hybridization analysis, and suggest how such findings will be taken forward over the next decade. With the search engine PUBMED, the key words "comparative genomic hybridisation," "head and neck," "oral," "hypopharyngeal," "laryngeal," and "squamous cell carcinoma" were used. Publications unavailable in English were excluded.

Chromosomal imbalances in laryngeal and hypopharyngeal cancers detected by comparative genomic hybridization

BACKGROUND

The prognostic divergence of laryngeal and hypopharyngeal carcinomas is well known. Hypopharyngeal tumors are characterized by frequent metastasis formation and local recurrence, which is the source of the unfavorable prognosis of this subtype. The aim of this study was to define chromosomal alterations associated with the aggressive behavior of hypopharyngeal tumors.

METHODS

Twenty-nine head and neck squamous cell carcinomas (larynx n = 14 and hypopharynx n = 15) were analyzed by comparative genomic hybridization (CGH). Fluorescence in situ hybridization (FISH) was used to validate the CGH data and to compare the amplification pattern of the most frequently altered gene (cyclin-D1, CCND1) located on 11q13.

RESULTS

The average number of genetic alterations was significantly higher in the hypopharyngeal tumors (P = 0.02). A good correlation of FISH and CGH data were seen. Gains on 11q13 were present in both subtypes, whereas amplification of CCND1 was associated with the aggressive phenotype by FISH. Chromosomal alteration, which was rarely detected in hypopharyngeal tumors but was observed in more than 50% of laryngeal carcinomas, was 8q gain.

CONCLUSION

Our CGH and FISH data show that head and neck squamous cell carcinomas contain complex cytogenetic alterations and further support the hypothesis that different molecular pathways are responsible for the progression of differently localized tumors of the upper aerodigestive tract.

Chromosomal alterations during lymphatic and liver metastasis formation of colorectal cancer

Comparative genomic hybridization (CGH) was used to screen colorectal carcinomas for chromosomal aberrations that are associated with metastatic phenotype. In total, 63 tumor specimens from 40 patients were investigated, comprising 30 primary tumors, 22 systemic metastases (12 liver, 6 brain, and 4 abdominal wall metastases) and 11 lymph node tumors. Using statistical analysis and histograms to evaluate the chromosomal imbalances, overrepresentations were detected most frequently at 20q11.2-20q13.2, 7q11.1-7q12, 13q11.2-13q14, 16p12, 19p13, 9q34, and 19q13.1-19q13.2. Deletions were prominent at 18q12-18q23, 4q27-4q28, 4p14, 5q21, 1p21-1p22, 21q21, 6q16-6q21, 3p12, 8p22-8p23, 9p21, 11q22, and 14q13-14q21. Hematogenous metastases showed more alterations than lymph node tumors, particularly more deletions at 1p, 3, 4, 5q, 10q, 14, and 21q21 and gains at 1q, 7p, 12qter, 13, 16, and 22q. Comparing liver metastases with their corresponding primary tumors, particularly deletions at 2q, 5q, 8p, 9p, 10q, and 21q21 and gains at 1q, 11, 12qter, 17q12-q21, 19, and 22q were more often observed. The analysis suggested that the different pathways of tumor dissemination are reflected by a nonrandom accumulation of chromosomal alterations with specific changes being responsible for the different characteristics of the metastatic phenotype.

Can a genetic signature for metastatic head and neck squamous cell carcinoma be characterised by comparative genomic hybridisation?

Survival from head and neck squamous cell carcinoma (HNSCC) has remained static for the last 20 years. The development of lymph node metastasis (LNM) significantly reduces the 5-year survival rate, thus the ability to identify tumours with the potential to metastasise would allow more aggressive treatment regimes to be directed at these patients regardless of negative clinical and radiological findings at the time of presentation. Comparative genomic hybridisation (CGH) can identify chromosomal aberrations that may lead to metastasis. DNA from 23-paired specimens of primary tumour (PT) and LNM were analysed. Nonrandom copy number changes were identified in all paired samples. Similar numbers of aberrations were identified on PT and LNM samples. The most common aberrations were 3q (90%), 8q (65%), 1q (50%), 5p (43%), 2q (41%) and 11q (41%) and deletions 3p (57%), 1p (54%), 4p (48%), 13q (48%), 11q (41%) and 10q (37%). A number of differences were also detected. No aberration was found to be preferentially associated with the LNM, although gains on 6q (48 vs 22%) and 22q (26 vs 9%) were found at higher frequencies. Clonality studies demonstrated that LNM develop from the dominant population of cells in the PT. These results were compared with two similar publications. No combination of chromosomal aberrations, as detected by CGH, was associated with metastatic progression in HNSCC.

Genetic abnormalities associated with nodal metastasis in head and neck cancer

BACKGROUND

Lymphatic metastasis represents the single most important clinical prognostic factor in head and neck squamous cell carcinoma (HNSCC), but underlying genetic mechanisms remain ill defined. Genetic differences between primary carcinomas and their corresponding metastases might form a key to understanding the metastatic phenotype. In this study we aimed to characterize such differences using a genome-wide screening measure.

METHODS

Four human cell lines (MDA-686tu, MDA-686Ln, MDA-1386tu, MDA-1386Ln) derived from primary tumor and synchronous lymph node metastasis of two cases of metastatic HNSCC were subjected to comparative genomic hybridization (CGH) by differentially labeling DNA from tumor tissue and normal tissue with fluorescent agents. The labeled DNAs were simultaneously hybridized onto normal metaphase chromosomes. In addition, modified CGH was performed by directly hybridizing labeled primary tumor DNA against differentially labeled metastatic tumor DNA, allowing the direct detection of copy number differences in individual pairs. Image analysis for fluorescence intensity along the entire length of each metaphase chromosome allowed generation of a color ratio, which was used to detect copy number changes.

RESULTS

In both cases, significant overlap was found between chromosomal aberrations present in the primary tumor and the corresponding nodal metastasis. However, several abnormalities differentiated primary tumors from their metastases. Modified CGH identified several genetic aberrations that were not detectable with the conventional CGH analysis. Gains at chromosomes 10p11-12 and 11p and deletions at chromosomes 4q22-31, 9p13-24, and 14q differentiated nodal metastases from the corresponding primary tumors in both cases.

CONCLUSIONS

The combination of conventional and modified CGH analyses facilitates the identification of DNA copy number changes that might be involved in the development of a metastatic phenotype. Future research should aim at the identification of the genes involved at the identified sites of chromosomal aberration.

Untreated chronic rhinosinusitis: a comparison of symptoms and mediator profiles

OBJECTIVES/HYPOTHESIS

Since the early 1990s, the knowledge of inflammatory mediators involved in chronic rhinosinusitis has increased extensively. However, until the present no data on trends in mediator levels in the natural course of the exacerbation-free interval of chronic rhinosinusitis have been published. The purpose of the study was to examine how levels of inflammatory mediators and clinical findings in chronic rhinosinusitis relate over time in the absence of acute exacerbation.

STUDY DESIGN

Prospective study.

METHODS

The authors investigated 12 untreated patients with chronic rhinosinusitis and repeated clinical examinations and measurements of inflammatory mediators in the nasal mucosa (messenger RNA [mRNA]of interleukin-1beta; interleukins 3, 5, 6, and 8 [IL-3, IL-5, IL-6, and IL-8]; interferon gamma; tumor necrosis factor-alpha [TNF-alpha]; monocyte chemotactic proteins 1, 3, and 4 [MCP-1, MCP-3, and MCP-4]; and granulocyte-macrophage colony-stimulating factor [GM-CSF]), as well as measurements of peptido-leukotriene [PLT] and prostaglandin E2 [PGE2]) in nasal secretion over a period of 4 weeks.

RESULTS

Clinically speaking, the symptom score significantly improved over the period of 4 weeks, whereas other clinical parameters (computed tomography score, endoscopy score, rhinomanometric values, saccharine transport time, ciliary beat frequency, and olfaction) varied insignificantly. Regarding proinflammatory and inflammatory mediators, only mRNA of IL-1beta, IL-6, IL-8, MCP-1, and TNF-alpha were detected in relevant amounts in nasal mucosa, and their levels decreased only insignificantly over the 4-week period. In nasal secretion, a slight decrease of PGE2 and PLT levels was observed over the same time period.

CONCLUSION

Subjective symptoms may show a spontaneous improvement of approximately 25% in patients with so-called "stable" chronic rhinosinusitis over a 4-week period, whereas objective clinical parameters vary insignificantly. Messenger RNA of IL-1beta, IL-6, IL-8, MCP-1, and TNF-alpha, as well as PLT and PGE2 levels, are detectable and appear to play a role in the persistence of inflammation in chronic rhinosinusitis. Their levels decrease only insignificantly over time, even in the absence of acute exacerbation of disease, possibly rendering the mucosa more prone to recurrent acute episodes.

Statistical analyses of karyotypic complexity in head and neck squamous cell carcinoma

More than 250 head and neck squamous cell carcinomas (HNSCCs) with clonal chromosomal abnormalities have been reported. Even though the pattern of aberrations is nonrandom, no specific primary or secondary karyotypic abnormalities have been identified. One explanation for the still-rudimentary understanding of the cytogenetic evolution in HNSCC could be the pronounced karyotypic complexity seen in these tumors. In an attempt to overcome this difficulty, we have applied several statistical methods such as hierarchical cluster analysis, multidimensional scaling, and k-means clustering, which allow the identification and interpretation of karyotypic pathways, as well as establishing a temporal order of chromosomal imbalances on 241 published and 70 previously unpublished HNSCC karyotypes. From the analysis of the distribution of the number of imbalances per tumor we suggest that the carcinomas evolve through three phases representing different stages of chromosomal instability. Two major cytogenetic pathways, one dominated by gains and another by losses, were identified by means of principal component analysis. These were initiated by +7 and by any of the aberrations 1p-, 3p-, or 7q-, respectively.

Quantitative DNA Measurement in Oropharyngeal Squamous Cell Carcinoma and Surrounding Mucosa

OBJECTIVE

The appearance of local recurrences, distant metastases and second primary tumors limit the survival rate of patients with head and neck squamous cell carcinomas. The presence of genetic alterations at the resection margins is an indicator of inadequate excision and a predictor of local failure.

DESIGN

To receive insight into the genetic abnormalities in the mucosa surrounding oropharyngeal cancers, we performed a quantitative DNA measurement in the primary tumor and the surrounding areas.

RESULTS

We found a high level of DNA irregularity in primary tumors. The DNA irregularity decreased in specimens taken at a distance of 1 and 2 cm from the tumor margin.

CONCLUSIONS

The genetically altered field is thought to determine the risk for recurrence of a second tumor. We therefore believe that the genetic analysis of tissue surrounding the tumor could become a feasible diagnostic procedure to determine the individual risk for local recurrence or second primary tumors.

DNA gains at 8q23.2: a potential early marker in head and neck carcinomas

Gains or amplifications involving chromosome arm 8q are one of the most recurrent chromosomal alterations in head and neck tumors. To characterize previously reported gains, we performed fluorescence in situ hybridization (FISH) using the sequences BAC RP1179E1 and 8-centromere PMJ 128 as probes. Gains and/or amplifications were detected in all 19 cases evaluated by FISH. The FISH analysis, but not G-banding, revealed homogeneously staining region in three cases. We conclude that gains of one or more genes on chromosome arm 8q may be important for the early stages of head and neck carcinomas.

Intratumoral genomic heterogeneity in advanced head and neck cancer detected by comparative genomic hybridization

Little is known about the extent of intratumoral genetic heterogeneity in head and neck squamous cell carcinoma (HNSCC). We therefore examined 79 stage III and IV primary HNSCCs (P) and matched lymph node metastases (M) for over- and underrepresentation of specific chromosome regions by comparative genomic hybridization (CGH). The overall ratio of gains and losses was higher in metastases than in primary tumors (4/1 vs. 2.5/1). Gains of 3q (78.1% P vs. 87.5% M) and 11q (78.1% P vs. 62.5% M) and deletions of 3p (43.8% P vs. 34.4% M) and 9p (31.3% P vs. 15.6% M) were most frequently detected. The highest rate of intratumoral discordance was observed for primary tumors and corresponding metastases (32.8%) compared with matched pairs of two metastases (26.5%) and of two anatomically distinct sides of one primary tumor (24.3%). Furthermore, the discordance rate was dependent on the primary tumor site (oral cavity 49.2%, oropharynx 31%, hypopharynx 30.3%, and larynx 27.3%). In some tumors, the extent of genomic discordance argues against a monoclonal origin. In conclusion, we found a high individual variation of intratumoral genomic heterogeneity depending on the localization and selection of matched pairs. These findings are of specific importance in view of establishing prognostic markers.

Chromosomal aberrations in premalignant and malignant squamous epithelium

Biopsies of oropharyngeal cancer were screened for chromosomal imbalances by comparative genomic hybridization (CGH) performed on 22 primary tumors and morphologically nonmalignant surrounding mucosa. The aim was to determine early chromosomal changes of tumor development and to draw conclusions on the mechanisms leading to multiple tumors. The most prominent chromosomal imbalances observed were over representations of genomic material on 3q, 15q, 8q, and 11q and losses on 9p, 3p, and 11q. In morphologically normal mucosa collected at 1 cm from the primary tumor border (M1), amplifications on 15q and 21q were most frequent. Far fewer gains and losses were found in M1 than in the primary tumor (average 2.2 vs. 6.9). Gains dominated over losses, but a tendency toward an increasing proportion of losses in the primary tumor (PT) was observed (ratio of gains to losses: PT, 4.75; M1, 6.3). Almost all the imbalances in M1 were detected in the primary tumor. No chromosomal alterations were identified with CGH in tissue samples dissected at 2 cm from the primary tumor (M2). In all samples, dysplastic morphologic changes decreased with distance from the primary tumor, which correlates with the observed lower level of genetic changes. We suggest that gains of genetic material on 15q and 21q are early events in malignant progression of squamous cell carcinoma, followed by gains on 3q, 8q, and 11q, and losses on 3p and 9p at later stages. Based on our cytogenetic data, we discuss the monoclonal model followed by lateral epithelial spread as an explanation of multiple head and neck squamous cell carcinomas.

Chromosomal aberrations related to metastasis of human solid tumors

The central role of sequential accumulation of genetic alterations during the development of cancer has been firmly established since the pioneering cytogenetic studies successfully defined recurrent chromosome changes in specific types of tumor. In the course of carcinogenesis, cells experience several genetic alterations that are associated with the transition from a preneoplastic lesion to an invasive tumor and finally to the metastatic state. Tumor progression is characterized by stepwise accumulation of genetic alterations. So does the dominant metastatic clone. Modern molecular genetic analyses have clarified that genomic changes accumulate during the development and progression of cancers. In comparison with the corresponding primary tumor, additional events of chromosomal aberrations (including gains or allelic losses) are frequently found in metastases, and the incidence of combined chromosomal alterations in the primary tumor, plus the occurrence of additional aberrations in the distant metastases, correlated significantly with decreased postmetastatic survival. The deletions at 3p, 4p, 6q, 8p, 10q, 11p, 11q, 12p, 13q, 16q, 17p, 18q, 21q, and 22q, as well as the over-representations at 1q, 8q, 9q, 14q and 15q, have been found to associate preferentially with the metastatic phenotype of human cancers. Among of them, the deletions on chromosomes 8p, 17p, 11p and 13p seem to be more significant, and more detail fine regions of them, including 8p11, 8p21-12, 8p22, 8p23, 17p13.3, 11p15.5, and 13q12-13 have been suggested harboring metastasis-suppressor genes. During the past decade, several human chromosomes have been functionally tested through the use of microcell-mediated chromosome transfer (MMCT), and metastasis-suppressor activities have been reported on chromosomes 1, 6, 7, 8, 10, 11, 12, 16, and 17. However, it is not actually known at what stage of the metastatic cascade these alterations have occurred. There is still controversial with the association between the chromosomal aberrations and the metastatic phenotype of cancer. As the progression of human genome project and the establishment of more and more new techniques, it is hopeful to make clear the genetic mechanisms involved in the tumor metastasis in a not very long future, and provide new clues to predicting and controlling the metastasis.

Comparative genomic hybridization analysis detected frequent overrepresentation of chromosome 3q in squamous cell carcinoma of the lung

The aim of this study was to provide cytogenetic data about squamous cell carcinomas of the lung and to evaluate their characteristic alterations and histogenetic relations. We analyzed 41 squamous cell lung carcinomas by comparative genomic hybridization (CGH) technique. CGH was performed using directly fluorochrome-conjugated DNA. Chromosomal regions where the mean ratio fell below 0.75 were therefore considered to reflect DNA copy number loss (underrepresentation), whereas regions where the mean ratio exceeded 1.25 were considered gains (overrepresentations) in the tumor genome. Overrepresentations were considered to be high-level amplification when the fluorescence ratio exceeded 1.5. Chromosomal imbalances were observed in every case. Copy number gains frequently were detected at 3q, 5p, 8q, 12p, and Xq. Losses were found at 16p, 4q, 5q, 3p, 17p, and 16q. DNA amplifications were observed at 12 regions: 3q26.1-27, 8q13-23.1, 12p12.3-pter, 12q15, 2p14-16, 4q28-31.2, 5p13.1-pter, 6q21-22.3, 7p11.2-13, 13q21.2-32, 18p11.2-pter, and 20p11.2-pter. Gains on 3q were frequently detected not only in the more than 3 cm group (79%) but also in the 3 cm or less group (77%). The mean frequency of gained or lost chromosomal regions was 7.2+/-4.7 in the 3 cm or less group (n=13) and 10.2+/-6.3 in the more than 3 cm group (n=28) (P=0.4503). The mean frequency of gained or lost chromosomal regions was significantly higher in the carcinoma with lymph node metastasis group (12.5+/-7.6 regions) (n=12) than in the carcinoma without lymph node metastasis group (7.9+/-4.6) (n=29) (P=0.0251). In conclusion, an increased copy number at 3q may contribute to the development of squamous cell carcinoma of the lung.

Cytogenetic studies of esophageal squamous cell carcinomas in the northern Chinese population by comparative genomic hybridization

Esophageal cancer is the fourth most prevalent malignancy in China. So far, the genetic events involved in esophageal cancer remain largely unknown. To identify chromosomal alterations in this disease, comparative genomic hybridization was performed on 25 primary tumors of esophageal squamous cell carcinomas. Results exhibited nonrandom copy number changes in chromosome DNA, with higher incidence in gain than in loss. The average gains and losses per patient were 7.76 and 4, respectively. The most common gains were 3q (20/25), 1q (15/25), 8q (15/25), 20p (12/25), 20q (11/25), 5p (10/25), 15q (8/25), and 9q (8/25) with two minimal amplification loci mapped to chromosomal regions of 8q24 (2 cases) and 11q13 (7 cases). High-level amplification was observed at 3q (8 cases), 5p (4 cases), and 8q (4 cases). Losses at 3p (10/25), 13q (8/25), 18q (7/25), Xp (7/25), 4 (6/25), 9p (6/25), 14q (6/25), 18p (6/25), and 21q (6/25) were identified. Remarkably, ten cases showed both loss of the entire 3p and overrepresentation of almost the whole 3q. No significant differences in stage or grade of tumor were found for DNA copy number changes. The results provided candidate regions for potential oncogenes and tumor suppressor genes related to Chinese esophageal cancer, to which further molecular studies should be addressed.

Genetic differences detected by comparative genomic hybridization in head and neck squamous cell carcinomas from different tumor sites: construction of oncogenetic trees for tumor progression

For a better understanding of genetic alterations in head and neck squamous cell carcinoma (HNSCC), we applied comparative genomic hybridization (CGH) in the analysis of 75 HNSCCs, comprised of 18 pharyngeal squamous cell carcinomas (PSCCs), 23 laryngeal squamous cell carcinomas (LSCCs), and 34 oral squamous cell carcinomas (OSCCs). The three subgroups of HNSCC showed significant differences in genetic alteration patterns. Overall, PSCC and LSCC had more copy number aberrations (CNAs) per tumor than did OSCC. Apparent differing patterns of high-level amplification were also observed. The smallest recurrent chromosomal regions of high-level amplification (> or = 15% of cases) were 7q22, 8q24.1, and 11q12-13 in PSCC and 3q26.1-29 in OSCC. According to single frequency and combined frequencies of CNAs, we concluded that the most important chromosomal events for progression of head and neck cancer were +3q, +5p, +8q, and -3p for all subgroups of HNSCC; additionally, +7q, +17q, -9p, and -13q for PSCC; +7p, +9q, +11q12-13, +14q, and +17q for LSCC; and +1p and +11q12-13 for OSCC. To identify further important genetic alterations and the relationships among the alterations, we constructed oncogenetic tree models for tumor progression of HNSCC from CGH data using branching and distance-based tree models. The tree models predicted that: (1) +3q21-29 was the most important early chromosomal event, and -3p, which occurred after +3q21-29, was also an important chromosomal event for all subsites of HNSCC; (2) +8q is the second most important early chromosomal event; (3) there may be at least three subgroups of HNSCC: one characterized by -3p, -9p, +7p, and -13q; another by +5p, +9qter, and +17p; and the other by +8q and +18p. These results suggest that different chromosomal aberrations may play a role in the initiation and/or progression of different subgroups of HNSCC.

Compilation of published comparative genomic hybridization studies

The power of comparative genomic hybridization (CGH) has been clearly proven since the first paper appeared in 1992 as a tool to characterize chromosomal imbalances in neoplasias. This review summarizes the chromosomal imbalances detected by CGH in solid tumors and in hemopathies. In May of 2001, we took a census of 430 articles providing information on 11,984 cases of human solid tumors or hematologic malignancies. Comparative generic hybridization has detected a number of recurrent regions of amplification or deletion that allows for identification of new chromosomal loci (oncogenes, tumor suppressor genes, or other genes) involved in the development, progression, and clonal evolution of tumors. When CGH data from different studies are combined, a pattern of nonrandom genetic aberrations appears. As expected, some of these gains and losses are common to different types of pathologies, while others are more tumor-specific.

Adhesive mechanisms regulating invasion and metastasis in oral cancer

It is the relentless invasion and growth into surrounding tissue that characterize oral squamous cell carcinoma. Metastasis is perhaps the most challenging and important aspect of cancer progression, in that it generally signifies limited survival and ineffective therapy. Inherent in metastasis is invasion, the process by which cells infiltrate into adjacent tissues, degrading basement membranes and extracellular matrix and disrupting tissue architecture and sometimes organ function. The factors that regulate these processes are complex and likely involve loss of the controls that are normally in place in physiologic tissue modeling. Adhesion receptors and their ligands are important in modulating not only invasion of oral squamous cell carcinoma cells but also their survival and proliferation. Normal oral mucosal epithelial cells use integrins to maintain their anchorage to the basement membrane, whereas the formation of stratifying cell layers depends on the formation of intercellular adhesions mediated by cadherins. The process of squamous cell carcinoma invasion and dissemination requires active cell migration through the extracellular matrix with the simultaneous remodeling of intercellular adhesions. Integrins are clearly important in the invasive process, whereas intercellular adhesion receptors restrain invasion and promote a more differentiated phenotype.

Chromosomal changes in betel-associated oral squamous cell carcinomas and their relationship to clinical parameters

To investigate the chromosomal imbalances that occur in oral carcinoma associated primarily with betel use and their clinical implications, we performed chromosomal analysis using comparative genomic hybridization on 47 patients with this disease. The most common gains of chromosome arms were 8q, 9q and 11q, and the most frequent losses were of chromosomal arms 3p and 4q. The clinical parameters significantly associated with the numbers of chromosomal imbalances per tumor were the age of the patients and nodal metastasis. The preliminary findings of a lower incidence of loss of 4q and gain of 8q in betel-associated tumors compared to non-betel-associated tumors might provide insight into the carcinogenic effect of betel. Deletion of 3p and the gain of 11q alterations were more prevalent in carcinomas with lymph node metastasis than in node-negative tumors, indicating possible loci for metastasis suppressor or metastasis enhancing genes, respectively. Losses of 3p and 4q and gain of 9q were associated with poor outcome for the patients. These data demonstrated that the frequent aberrations in 4q and 9q sites can be used as novel prognostic predictors.

Karyotypic heterogeneity and clonal evolution in squamous cell carcinomas of the head and neck

Head and neck squamous cell carcinomas (HNSCC) are often characterized by complex karyotypic changes, and a substantial proportion of the reported tumors have shown intratumor heterogeneity in the form of cytogenetically related (40%) or unrelated clones (20%). In order to study intratumor heterogeneity and to distinguish the temporal order of chromosome rearrangements in these tumors, two or more samples from different areas of the same tumor were separately examined in 19 HNSCC, yielding karyotypes from a total of 42 tumor samples. Intrasample heterogeneity was observed in 16 samples. Two samples displayed both related and unrelated multiple clones, four samples showed only multiple unrelated clones, and the remaining 10 samples had only related subclones. Intersample heterogeneity was detected in all but one tumor. Five tumors showed both cytogenetically related and unrelated multiple clones, 11 were found to have only related subclones, and the remaining two tumors showed only unrelated clones. Clonal evolution could be assessed in 13 tumors. A comparison of chromosome imbalances in different subclones from these tumors suggests that partial or entire loss of 3p, 8p, 9p, and 18q and gain of genetic material from 3q and 8q are likely to be early genetic events. In contrast, loss of 1q, 6p, 7q, and chromosome 10, as well as gain of chromosome arms 5p and 7p, are most probably later genetic events. One of the examined tumors contained two highly complex clones that were cytogenetically unrelated, indicating that this tumor had a multicellular origin.