Oral leukoplakias show numerical chromosomal aberrations detected by fluorescence in situ hybridization

Reference spectra from squamous epithelium and connective tissue allow whole section proteomics analysis

We reasoned that micro-dissection of tumour cells for protein expression studies should be omitted since tumour-stroma interactions are an important part of the biology of solid tumours. To study such interactions in head and neck squamous cell carcinoma (HNSCC) development, we generated reference protein spectra for normal squamous epithelium and connective tissue by SELDI-TOF-MS. Calgranulins A and B, Annexin1 and Histone H4 were found to be strongly enriched in the epithelium. The alpha-defensins 1-3 and the haemoglobin subunits were identified in the connective tissue. Tumour-distant epithelia, representing early pre-malignant lesions, showed up-regulated expression of the stromal alpha-defensins, whereas the epithelial Annexin 1 was down-regulated. Thus, tumour microenvironment interactions occur very early in the carcinogenic process. These data demonstrate that omitting micro-dissection is actually beneficial for studying changes in protein expression during development and progression of solid tumours.

Organotypic co-cultures allow for immortalized human gingival keratinocytes to reconstitute a gingival epithelial phenotype in vitro

We report here that the organotypic co-culture (OCC) system allows for significant preservation of the tissue-specific phenotype of human gingival keratinocytes (IHGK) immortalized with the E6/E7 gene of the human papillomavirus type 16 (HPV16). The approach adopted is based on the OCC system facilitating spatially separated cell growth and cell-to-cell interactions via diffusible growth factors. Generally, IHGK reveal transcription of the HPV16 E6/E7 gene at rising passages. Fluorescence in situ hybridization performed for chromosomes 1, 8, 10, and 18 demonstrates that disomic fractions differ between the tested chromosomes but otherwise remain fairly constant. Monosomies of chromosome 18 are more prominent in late passages 81 and 83, while polysomies of chromosome 10 and 18 are detected in early passages 25 and 27. In comparison with corresponding monolayer cultures (MCs), IHGK in OCCs form stratified epithelia, proliferate, and express gingival-specific gene products in vitro. Moreover, mRNA gene transcription for growth factors interleukin 1beta, granulocyte-macrophage colony stimulating factor, fibroblast growth factor 7, and EGF in OCCs is different from that in MCs. When grafted onto nude mice, IHGK develop hyperplastic, differentiated surface epithelia devoid of malignant growth. We are not aware of any other OCC system comprising of IHGK, which allows for site-specific expression of gingival epithelial markers. This substantiates reconstitution of a gingival epithelial phenotype in vitro.

Numerical aberrations of chromosomes 8, 9, 11, and 17 in squamous cell carcinoma of the pharynx and larynx: a fluorescence in situ hybridization and DNA flow cytometric analysis of 50 cases

Squamous cell carcinoma of the pharynx and larynx (SCCPL) is a genetically complex disease and is frequently associated with nonrandom chromosomal alterations. Fifty primary SCC of the pharynx (oropharynx, n=11): see and hypopharynx, n=11) and larynx ( n=28) were examined for numerical aberrations of chromosomes 8, 9, 11, and 17 with a panel of chromosome-specific repetitive DNA probes by fluorescence in situ hybridization (FISH). DNA ploidy analysis was also performed by flow cytometry (FCM). Aneusomic copy numbers of chromosomes 8, 9, 11, and 17 were discovered in 66%, 68%, 68% and 78% of tumors, respectively. FCM showed abnormal DNA content in 74% of cases (mean DNA index=1.69). Polysomy was the main finding in both DNA-aneuploid and DNA-diploid tumors (64.5% of cases). Numerical aberrations of chromosomes 8 and 11 correlated to DNA ploidy by FCM (P< 0.05). Aneusomy was present in 69.23% of DNA-diploid tumors. Marked intratumoral and intertumoral chromosomal heterogeneity was noted between individual tumors, suggesting a notable heterogeneity in aneuploid and diploid cell populations. Interphase FISH can be used to study important cytogenetic changes which occur during the development of SCC of the pharynx and larynx.

p53-Positive Tumor-Distant Squamous Epithelia of the Head and Neck Reveal Selective Loss of Chromosome 17

OBJECTIVES/HYPOTHESIS

The progression of clinically manifest premalignant lesions in the head and neck region to primary or second primary cancer is characterized by numerical and structural chromosomal aberrations. However, many tumors arise from histologically inconspicuous mucosal sites. The objective was to investigate whether chromosomal aberrations can be detected in tumor-distant mucosa and whether they can help predict the risk of second primary malignancy.

STUDY DESIGN

A retrospective series of 72 clinically healthy, arbitrarily taken mucosal samples from 53 patients with squamous cell carcinoma of the head and neck was studied. A previous analysis of the p53 protein status had revealed both p53-positive and p53-negative samples.

METHODS

The samples were analyzed by fluorescence in situ hybridization (FISH) using centromeric probes specific for the chromosomes 1, 10, 17, and 18.

RESULTS

Tumor-distant mucosa generally showed increased numerical chromosomal aberrations, which consisted mainly of monosomies. In the group of patients with p53-positive epithelia, all aberrations including gains of chromosomes (trisomies, tetrasomies) were more frequent. Monosomy for chromosome 17 was most significantly and selectively enhanced in this group (Wilcoxon Scores [rank sum] test, P =.0002).

CONCLUSION

Detectable chromosomal aberrations occur in clinically healthy epithelia in patients at risk for secondary head and neck cancer. Specifically, unbalanced chromosome 17 monosomy in conjunction with p53 protein overexpression may constitute a valuable biomarker for progressive "field cancerization."

Fluorescence in situ hybridization analysis of HER-2/neu in brushings of normal oral mucosa

Oncogene alterations have been clearly demonstrated to be related to the carcinogenesis and progression of oral squamous cell carcinoma (OSCC). However, the analysis of these alterations for screening and early diagnostic purposes generally requires invasive techniques for surgical removal of pathological epithelium. The aim of the present study was to assess the feasibility of fluorescence in situ hybridization (FISH) analysis of HER-2/neu amplification in oral mucosa brushings and to compare the HER-2/neu status with the history and smoking and drinking habits of healthy subjects. Cells obtained by centrifugation of oral brushings from 21 subjects (overall no. of cells: 5125) were suspended in physiological saline and fixed onto two slides for cytological evaluation and FISH analysis (dual-target, dual-color fluorescence assay) of the HER-2/neu gene and CEP17 centromere. A mean of 89.8% of the cells showed two HER-2/neu signals and a mean of 94% had two CEP17 signals at fluorescent microscopy. Finally, a mean of 96% of cells with HER-2/neu / CEP17 had a ratio equal to 1. No association between smoking and drinking habits, age and the HER-2/neu and CEP17 characteristics evaluated by FISH was found.