Molecular cytogenetic characterization of the 11q13 amplicon in head and neck squamous cell carcinoma

Amplification of 11q13 DNA sequences and overexpression of CCND1 are common findings in head and neck squamous cell carcinoma (HNSCC), identified in about 30% of the cases. However, little is known about initiation of the amplification and the organization of the amplicon. In order to study the structure of the amplicon in more detail and to learn more about the mechanisms involved in its initiation, prometaphase, metaphase, and anaphase fluorescence in situ hybridization (FISH) with 40 BAC clones spanning a 16-Mb region in chromosome bands 11q12.2 to 11q13.5 was performed in nine HNSCC cell lines with homogeneously staining regions. FISH analysis showed that the size of the amplicon varied among the nine cell lines, the smallest being 2.12 Mb and the largest 8.97 Mb. The smallest overlapping region of amplification was approximately 1.61 Mb, covering the region from BAC 729E14 to BAC 102B19. This region contained several genes previously shown to be amplified and overexpressed in HNSCC, including CCDN1, CTTN, SHANK2, and ORAOV1. The cell lines were also used to study the internal structure of the amplicon. Various patterns of amplified DNA sequences within the amplicon were found among the nine cell lines. Even within the same cell line, different amplicon structures could be found in different cell populations, indicating that the mechanisms involved in the development of the amplicons in HNSCC were more complex than previously assumed. The frequent finding of inverted repeats within the amplicons, however, suggests that breakage-fusion-bridge cycles are important in the initiation, but the fact that such repeats constituted only small parts of the amplicons indicate that they are further rearranged during tumor progression.

Low expression of fragile histidine triad gene correlates with high proliferation in head and neck squamous cell carcinoma

Frequent loss of heterozygosity in head and neck squamous cell carcinoma (HNSCC) has been found in several chromosomal regions such as 3p, 9p, 11q, 13q and 17p. Fragile histidine triad (FHIT) gene is located at 3p14.2 encompassing a common fragile site, and is identified as a tumor suppressor gene. We examined 57 patients with HNSCC using immunohistochemistry, western blot, and reverse transcriptase polymerase chain reaction. The association between FHIT expression and clinicopathologic characteristics including p53 and Ki-67 expressions was analyzed. Immunohistochemical analysis revealed 30 patients (53%) of low FHIT expression and 27 patients (47%) of high FHIT expression. Low FHIT expression significantly correlated with high Ki-67 expression, indicating that tumor cells with low FHIT expression can proliferate aggressively. No correlation was found between FHIT expression and clinical characteristics including age, gender, tumor size, lymph node status, stage grouping, histologic grade, p53 expression, and prognosis. FHIT alteration may play an important role in cancer development of HNSCC, however it did not contribute to the prognosis.

Cytogenetic and fluorescence in situ hybridization characterization of chromosome 8 rearrangements in head and neck squamous cell carcinomas

Structural rearrangements of chromosome 8 are frequently encountered in squamous cell carcinomas of the head and neck (HNSCC). These aberrations often affect the centromeric region, resulting in the formation of isochromosome i(8q) and whole arm translocations. Some tumors may display structural rearrangements of 8p23. To characterize further the localization of the breakpoints in such rearrangements, 12 HNSCC known to carry pericentromeric rearrangements of chromosome 8 and 8p23 abnormalities were investigated with fluorescence in situ hybridization (FISH) by the use of 15 YAC clones spanning 8p23 and 8p11 to 8q11. FISH confirmed that all, except one, aberrations cytogenetically interpreted to be i(8q) were true, monocentric i(8q). Similarly, all whole-arm translocations appeared as centric fusions. It could thus be concluded that the essential outcome of these rearrangements is genomic imbalances and not rearrangement of genes in the pericentromeric region. By the use of five YAC clones mapping to 8p23, different breakpoints at the molecular level were disclosed in cases with cytogenetically identical 8p23 rearrangements. An evaluation of the genomic imbalances detected in the present series revealed that overrepresentation of 8q material was present in 11 of the 12 tumors. The most commonly gained segment was 8q22 approximately qter, found in all cases with 8q overrepresentation. Loss of parts of or the entire 8p was seen in 10 tumors. The smallest overlapping deleted region was localized to the subtelomeric region of 8p.

Cyclin D1 overexpression versus response to induction chemotherapy in squamous cell carcinoma of the head and neck--preliminary report

The aim of this study was to investigate whether there is an association between overexpression of cyclin D1 and response to therapy. Immunohistochemical overexpression of cyclin D1 was determined in paraffin-embedded specimens from diagnostic biopsies of 89 primary cases of squamous cell carcinoma of the head and neck (SCCHN), using a polyclonal antiserum. The tumor response rates were estimated after curative treatment (i.e. surgery and/or radiotherapy and/or chemotherapy). Patients whose tumors were overexpressing cyclin D1 showed complete or partial response to neoadjuvant chemotherapy with cisplatin/5-FU. In addition, a majority of cyclin D1 negative tumors did not respond at all to this treatment (p = 0.02, Fisher's exact test). This study indicates that immunohistochemical assessment of cyclin D1 expression in SCCHN could be a new predictive marker to select a subgroup of patients that will benefit from neoadjuvant chemotherapy.

Antitumor effect of radioactive cisplatin (191Pt) on nude mice

PURPOSE

To investigate the effect of (191)Pt-cisplatin in vivo in terms of the antitumor effect and general toxicity on tumor-bearing nude mice.

METHODS AND MATERIALS

Tumor-bearing (human squamous cell carcinoma, AB) nude mice were divided into four groups and given, i.p., physiological saline (controls), cisplatin, (191)Pt-cisplatin (80 MBq/mg), or (191)Pt-cisplatin (160 MBq/mg), respectively. Mortality and weight were used as parameters for monitoring general toxic effect, while specific growth delay (SGD) and the area under the logarithm of the relative tumor size curve (AUC-log[RTS]) were used to evaluate the antitumor effect of the treatments.

RESULTS

Both SGD and AUC-log(RTS) values showed that (191)Pt-cisplatin was significantly (P < 0.05) more effective in retarding tumor growth than nonradioactive cisplatin. No differences in mortality between the different groups could be observed and no significant differences in weight change between the mice treated with cisplatin or (191)Pt-cisplatin could be seen.

CONCLUSION

(191)Pt-cisplatin is a more effective drug than nonradioactive cisplatin in retarding tumor growth on nude mice without adding systemic toxic effects. We believe that radioactive cisplatin may prove to be an alternative to conventional cisplatin; however, the possible toxic effects on organs at risk have to be thoroughly investigated.

Characterization of chromosome aberrations in salivary gland tumors by FISH, including multicolor COBRA-FISH

Fluorescence in situ hybridization (FISH), including COBRA-FISH, was used to characterize 11 salivary gland tumors that had been investigated by banding analysis. Five cases were pleomorphic adenoma (PA), three were adenoid cystic carcinoma, and one case each was mucoepidermoid carcinoma, carcinoma ex-pleomorphic adenoma (CaPA), and adenocarcinoma. All 11 cases were selected on the basis that they had shown rearrangement of 6q or 9p or had unresolved aberrations after karyotyping. The COBRA-FISH and FISH analyses led to a revised karyotype in all informative cases and made it possible to clarify almost all chromosomal rearrangements occurring in the tumors. Of particular note were the confirmation of the existence of 6q deletions, a common change in salivary gland carcinomas, and the demonstration that a seemingly balanced t(6;9) resulted in del(6q). Other rearrangements that were revealed by FISH included amplification of 12q sequences (MDM2 and CDK4) in one PA. We also investigated the status of the PLAG1 gene in four cases (one PA, one CaPA, one adenoid cystic carcinoma, and one mucoepidermoid carcinoma) with 8q12 rearrangements. Only in the former two cases were the FISH results compatible with intragenic rearrangements. Overall, the results of the study show that, even with good banding quality and in karyotypes of modest complexity, much new information will be gained by supplementing the banding analysis with a multicolor FISH approach, such as COBRA-FISH.

Centromere cleavage is a mechanism underlying isochromosome formation in skin and head and neck carcinomas

Centromeric rearrangements, in the form of isochromosomes or whole-arm translocations, are the most common recurrent changes in head and neck and skin carcinomas. Little is known about the mechanisms behind the origin of these chromosome rearrangements. In the present study, one basal cell carcinoma and two squamous cell carcinomas of the head and neck were thoroughly studied by cytogenetic and fluorescence in situ hybridization techniques. All tumors showed intratumor heterogeneity in the form of cytogenetically related subclones (in all tumors) and unrelated clones (in one tumor). Assessment of karyotypic evolution in these tumors suggests that centromeric cleavage is a mechanism giving rise to isochromosomes. A similar mechanism may also be involved in the formation of whole-arm translocations.

Prognostic value of vascular endothelial growth factor (VEGF) in head and neck squamous cell carcinomas

Vascular endothelial growth factor (VEGF) has been identified as the substance that increases the permeability and proliferation of vascular endothelial cells. We examined the clinical significance of VEGF expression in 60 head and neck squamous cell carcinomas using the methods of Western blot, immunohistochemistry, and reverse transcriptase-polymerase chain reaction (RT-PCR), comparatively, and analysed the relationship between VEGF status in Western blot and tumour size, lymph-node status, histologic grade and disease-free survival (DFS) rate. Western blot analysis revealed high VEGF expressors (tumour/normal tissue density >/= 3-fold) in 26 patients (43%) and low VEGF expressors (< 3-fold) in 34 patients (57%). The results of the Western blot analysis correlated significantly with those of the RT-PCR (P = 0.00007) or immunohistochemistry (P = 0. 00006). High VEGF expressors are associated with the progression of lymph-node spread (P = 0.0009), which are correlated with poor DFS. The 2-year DFS rate of high VEGF expressors (30%) was significantly lower than that of low VEGF expressors (78%) (P = 0.0008). Multivariate analysis showed VEGF expression and stage were independent predictors for the DFS (P = 0.045 and 0.041, respectively). VEGF expression may play an important role in progression of HNSCC.

Nonrandom pattern of cytogenetic abnormalities in squamous cell carcinoma of the larynx

Cytogenetic analysis of short-term cultures from 105 squamous cell carcinomas of the larynx (LSCC) revealed clonal chromosome aberrations in 56 tumors. Simple karyotypic changes (less than four aberrations per clone) were found in 24 cases, and the remaining 32 tumors had complex karyotypes with multiple numerical as well as unbalanced structural rearrangements. Extensive intratumor heterogeneity, in the form of multiple related subclones or unrelated clones, was observed in a large fraction of the tumors. The structural changes most often affected chromosomes 3, 1, 11, 7, 2, 15, 5, 4, 8, and 12, with rearrangements in the centromeric regions, i.e., the centromeric bands p10 and q10 and the juxtacentromeric bands p11 and q11, accounting for 43% of the total breakpoints. The most common imbalances brought about by numerical and unbalanced structural rearrangements were loss of chromosomal region 3p21-pter, chromosome arms 4p, 6q, 8p, 10p, 13p, 14p, 15p, and 17p, and gain of chromosomal regions 3q21-qter, 7q31-pter, and 8q. Among 17 recurrent aberrations identified, the most common were i(8q), hsr(11)(q13), i(3q), i(5p), and del(3)(p11). No statistically significant association was found between major karyotypic features and histological differentiation or TNM stage. The karyotypic features of the LSCC were also compared with previously published oral SCC, a subgroup of SCC that has been more extensively characterized cytogenetically. No clear-cut karyotypic differences were found between LSCC and oral SCC, with the exception that i(8q) was significantly more frequent among the latter.

Distribution of non-diploid flow-cytometric DNA indices and their relation to the nodal metastasis in squamous cell carcinomas of the head and neck

Squamous cell carcinomas of the head and neck (HNSCC) evolve from diploid epithelial cells of the mucosa. At the time of diagnosis about two thirds of clinically diagnosed HNSCC are non-diploid according to flow-cytometric (FCM) analysis, indicating that during tumour progression there must be an acquisition and accumulation of chromosomal aberrations. At diagnosis one third to one half of HNSCC have clinically positive neck nodes. The objective of the present study was to see whether the progression to a metastatic phenotype is reflected in the distribution of FCM DNA ploidy in node-negative and node-positive HNSCC. The series comprised 200 patients with HNSCC. Tumour samples were obtained from diagnostic biopsies or primary surgery. A multistep preparation method and propidium iodide staining of nuclear DNA content was used for FCM. One hundred and forty one (71%) of the tumours were non-diploid. Only two tumours were hypodiploid (DNA index 0.73 and 0.93, respectively). Ten of the tumours exhibited two non-diploid stem cell lines. The frequency of non-diploidy in node-negative tumours was 65% and in node-positive ones about 80%. The frequency distribution of non-diploid DNA indices clustered in the hypotetraploid region (with a modal value of 1.71-1.74) and did not differ between node-negative and node-positive tumours. The hypothesis that the disposition to metastasis is reflected in the frequency distribution of non-diploid DNA indices could thus not be verified.

In vitro toxicity of (191)Pt-labeled cisplatin to a human cervical carcinoma cell line (ME-180)

PURPOSE

The aim of the present work was to examine the effect of (191)Pt-cisplatin, and to study the manner in which radiation and cisplatin interact, in a human cervical carcinoma cell line (ME-180).

METHODS AND MATERIALS

The cells were incubated for 1 hour with nonradioactive cisplatin or (191)Pt-cisplatin with specific activities in the range 48-167 MBq/mg. The surviving fraction of the cells after 7 days' growth was determined with a nonclonogenic tetrazolium-based (MTT) assay. The uptake of platinum into the cell and the amount of platinum bound to DNA was measured.

RESULTS

The 50% inhibition concentration (IC(50)) decreased with increasing specific activity of the (191)Pt-cisplatin. For the specific activities 0 (nonradioactive), 48, 89, 143, 157, and 167 MBq/mg, IC(50) was found to be 3.24 +/- 0.08, 2.77 +/- 0.55, 2.17 +/- 0.34, 1.15 +/- 0.04, 1.02 +/- 0.03, and 0.76 +/- 0.13 respectively. Isobologram analysis showed a supra-additive (synergistic) interaction between the radiotoxicity and chemotoxicity for specific activities over 100 MBq/mg.

CONCLUSION

The cytotoxic effect of cisplatin may be enhanced by labeling the drug with the radionuclide (191)Pt.

Cyclin D1 overexpression correlates with poor prognosis in patients with tongue squamous cell carcinoma

Tongue squamous cell carcinoma makes up a large percentage of head and neck cancers, and the incidence among young patients is increasing. The aim of this study was to reveal the correlation between cyclin D1 (CCND1) expression and clinical and histologic features. We performed an immunohistochemical study on the level of CCND1 expression in tumor specimens obtained from 94 patients with tongue squamous cell carcinoma. The relationship between the expression and the following features such as age, sex, smoking and alcohol intake history, T, N, histologic grade, and multiple primary cancer was analyzed. Eighteen patients (19%) showed CCND1 overexpression (tumor cell nuclei positivity >/=50%). The 5-year survival rate of high CCND1 expressors was 39%, which was significantly poor (p=0.04). N classification correlated with CCND1 expression. CCND1 overexpression is associated with poor survival associated with progression of lymph node spread in patients with tongue squamous cell carcinomas. CCND1 expression may be a useful biologic marker for prognosis.

Nonrandom karyotypic features in squamous cell carcinomas of the skin

We report the finding of clonal chromosome abnormalities in 13 short-term cultured squamous cell carcinomas (SCCs) of the skin. Intratumor heterogeneity, in the form of cytogenetically related (subclones) or unrelated clones, was detected in six tumors. Whereas clones with complex karyotypic changes were found in 6 tumors, clones with simple anomalies were observed in 10 tumors, and sometimes these clones coexisted with highly abnormal clones. Rearrangement of chromosome 8, in the form of isochromosome i(8q) or whole arm translocation, was the most common aberration, found predominantly in complex clones. Another recurrent feature, i.e., the centromeric rearrangement of chromosome 1, as isochromosome i(1q) or i(1p), or whole arm translocations, was always part of a complex karyotype. Homogeneously staining regions were found in two cases, one with a highly complex karyotype and the other with a simple karyotype. In order to obtain an overall karyotypic picture in SCC of the skin, the cytogenetic findings in 10 SCCs reported earlier were reviewed. The chromosomes most commonly affected were, in decreasing order, chromosomes 1, 11, 8, 9, 5, 3, and 7. Chromosomal sites most frequently rearranged were almost all pericentromeric: they were 8q10-q11, 1p10-q12, 5p10-q11, 11p15, and 9p10-q10. Recurrent anomalies were i(1q), i(8q), i(5p), i(1p), i(9p), and i(9q). Among them, only i(8q) and i(9q) might be assumed to be early genetic events, considering the fact that they could occasionally be identified in simple clones. The most frequent losses included part of or the entire chromosomes 2, 4, 9, 11, 14, 18, and 21, arm 8p, and chromosomes X, Y, and 13. Overrepresentation most frequently involved 1q, chromosome 7, and 8q. The characteristic karyotypic pattern observed in skin SCC was in line with the experience in several other carcinomas. Genes Chromosomes Cancer 26:295-303, 1999.

Abnormal cell cycle regulation in malignancy

The cell cycle consists of an initial growth phase (G1), DNA replication (S), a gap phase (G2), and mitosis (M), after which the cell may differentiate or enter the resting state (G0). The cycle is driven by a number of positive and negative regulatory phosphorylation and dephosphorylation events, involving protein kinases, protein phosphatases, cyclins, cyclin-dependent kinases, and cyclin-dependent kinase inhibitors, that ultimately impinge on the activity of transcription factors. Unreplicated or damaged DNA blocks the progression of the cell cycle at checkpoints, including a late G1 checkpoint regulated by the dephosphorylated retinoblastoma protein and a late G2 checkpoint regulated by the phosphorylation of cyclin-dependent kinase 1 complexed with cyclin B. Many cell cycle regulator genes may be considered proto-oncogenes or tumor suppressor genes, and point mutations, amplifications, deletions, or rearrangements involving their loci, particularly those in the "RB pathway," are associated with various tumors. A number of molecular techniques may be used to detect genomic alterations or posttranscriptional modifications, but immunohistochemistry remains the most common method to determine expression levels of a regulatory protein. Multivariate analysis of the usefulness in prognosis has been applied most often for the general proliferation antigen Ki-67.

Amifostine as a protector against cisplatin-induced toxicity in nude mice

The mechanisms mediating the protective effects of amifostine on cisplatin-induced toxicity were investigated in tumor-bearing nude mice by quantitative immunohistochemistry for analysis of cisplatin-DNA adduct levels in tumors and kidneys. The mice were treated with cisplatin 5 or 10 mg/kg i.p. with or without amifostine 200 mg/kg 30 min prior to cisplatin. Toxicity was noted in terms of mortality and changes in body weight. Mortality was similar in the four treatment groups, regardless of cisplatin dose or whether amifostine was added or not. At a cisplatin dose of 5 mg/kg, amifostine did not affect the moderate decrease in body weight. Cisplatin 10 mg/kg alone gave a significant loss of body weight, with the nadir on day 7. By adding amifostine to 10 mg/kg cisplatin the weight loss was much less pronounced. Tumor growth was significantly more retarded among animals treated with 10 mg/kg cisplatin alone compared with amifostine + cisplatin 10 mg/kg. There was no difference in tumor growth retardation between cisplatin 5 mg/kg alone or in combination with amifostine. The most likely explanation was that the pronounced tumor growth retardation with 10 mg/kg cisplatin alone was due to the decline in the general condition of the animals rather than increased antitumoral activity per se. Analysis of cisplatin-DNA adducts in tumors showed no difference whether cisplatin 10 mg/kg was combined with amifostine or not. In kidneys there were significantly fewer tubular cells with very high adduct levels in animals pretreated with amifostine.

Fluorescent in situ hybridisation (FISH) characterisation of pericentromeric breakpoints on chromosome 5 in head and neck squamous cell carcinomas

Pericentromeric rearrangements, such as isochromosomes and whole-arm translocations, are frequently encountered in short-term cultures from head and neck squamous cell carcinomas (HNSCC). To characterise further the localisation of the breakpoints in such rearrangements, metaphase cells from seven HNSCC known to carry structural rearrangements of the pericentromeric region of chromosome 5 were investigated using fluorescent in situ hybridisation (FISH) techniques. With a whole chromosome painting probe it could be confirmed that all chromosome 5 rearrangements identified at cytogenetic analysis contained chromosome 5 material. By using a centromere-specific alpha satellite probe it could be shown, however, that cytogenetically identical derivative chromosomes had different breakpoints. Thus, we conclude that the results of the present investigation add further support to the hypothesis that the essential outcome of near-centromeric chromosome rearrangements is the creation of genomic imbalances, i.e. gain and/or loss of neoplasia-associated genes.

Cytogenetic and fluorescence in situ hybridization characterization of chromosome 1 rearrangements in head and neck carcinomas delineate a target region for deletions within 1p11-1p13

Cytogenetic analyses have revealed structural rearrangements of chromosome 1 in a large fraction of head and neck carcinomas (HNCA). These aberrations frequently affect chromosomal band 1p13 and the centromeric region, the latter often in the form of isochromosome i(1q) and whole-arm translocations. To delineate the critical region involved in rearrangements of proximal 1p, we have undertaken a more precise breakpoint mapping in 13 HNCAs, using metaphase fluorescence in situ hybridization with 11 yeast artificial chromosome (YAC) clones spanning 1p. All of the tumors had chromosome 1 changes at G-banding analyses. Fluorescence in situ hybridization showed that in almost all of the cases, at least one copy of chromosome 1 was affected by centromeric rearrangement. By the use of YAC clones mapped to juxtacentromeric regions and a centromere-specific alpha-satellite probe, we detected variable breakpoints in the whole-arm translocations. At the cytogenetic level, 1p13 rearrangements were frequent. However, molecular breakpoints within this band varied among the HNCAs tested. The lack of consistently rearranged chromosome segments indicates that the pathogenetically important consequence of 1p rearrangements in HNCAs is loss and/or gain of genes outside the breakpoint regions. In an assessment of the genomic imbalances, partial or complete overrepresentation of 1q was seen in eight cases. Loss of 1p material was also identified in eight cases; and in four of them, the deleted segments were too small to be discovered by G-banding analysis. The minimal overlapping deleted region was in the interval between YAC 959C4 (band p11-p12) and the centromere (p10). Our findings indicate that a target region potentially harboring tumor suppressor gene(s) crucial for HNCA is located within chromosomal bands 1p11-p13.

p53 mutation, but not p53 overexpression, correlates with survival in head and neck squamous cell carcinoma

Survival in squamous cell carcinoma of the head and neck (HNSCC) was compared with overexpression and mutation of the p53 gene. Archival tissue from 77 tumours was analysed for protein expression using immunohistochemistry (IHC) with the monoclonal antibody Do-7, and for the presence of mutation in exons 5-8 using single-stranded conformation polymorphism (SSCP), followed by DNA sequencing in SSCP-positive cases. p53 expression was scored as high (>70% nuclei stained) in 25 (32%) tumours, as intermediate (10-70% nuclei stained) in 19 (25%) tumours and as low (<10% nuclei stained) in 33 (43%) tumours. Twelve (18%) tumours exhibited gene mutation (ten missense and two nonsense mutations) and an additional five tumours contained changes that could not result in amino acid substitution or protein truncation. There was no correlation between gene expression and mutation, mutations being equally frequent in tumours with either high (4/25), intermediate (4/19) or low protein expression (4/33). Fifty-eight patients were eligible for survival analysis. There was a strong correlation between p53 mutation and cause-specific survival; median survival among mutated cases was 12.5 months compared with >160 months among non-mutated patients (P < 0.005). There was no correlation between p53 overexpression and survival. The results suggest that p53 mutation status is an important prognostic factor in HNSCC, and that IHC analysis of protein overexpression is an inadequate measure of gene mutation in these tumours.

FISH characterization of head and neck carcinomas reveals that amplification of band 11q13 is associated with deletion of distal 11q

In order to characterize homogeneously staining regions (HSR) and other 11q13 rearrangements identified cytogenetically, we performed fluorescence in situ hybridization (FISH) using a CCND1 cosmid and five YAC clones spanning chromosomal bands 11q13-14 on metaphase cells from 14 primary and one metastatic head and neck carcinomas. At the cytogenetic level, a total of 17 HSR were detected in ten cases: five were in derivative chromosomes 11 in band 11q13, and 12 were located in other derivative chromosomes. Other forms of 11q13 rearrangements were observed in five cases, whereas two cases had normal chromosomes 11. FISH analysis demonstrated that all HSR but two were derived from the 11q13 band. The size of the amplicon varied from case to case, but the amplification always included the region covered by YAC 55G7, which contains the CCND1 locus. The amplification of CCND1 was confirmed by use of a CCND1 cosmid. We also showed that most of the cases (9 of 11) with 11q13 amplification had lost material from distal 11q. The breakpoints were mapped by FISH and were shown to cluster to the region between YACs 55G7 and 749G2. We conclude that loss of gene(s) in distal 11q may be as important as amplification of genes in 11q13 for the biological aggressiveness of head and neck carcinomas.

Cytogenetic and molecular genetic demonstration of polyclonality in an acinic cell carcinoma

The paradigm that human malignancies are monoclonal has been questioned during recent years by the finding of unrelated, cytogenetically aberrant clones in short-term cultures from certain tumour types, notably carcinomas of the breast, skin and upper aerodigestive tract. In order to analyse whether cytogenetically unrelated clones are also unrelated at the molecular level, we analysed the X-chromosome inactivation status in cell cultures from a cytogenetically highly polyclonal acinic cell carcinoma of the parotid gland. By using cell cultures dominated by a single abnormal clone, obtained through in vitro culturing for 3-5 passages, we showed that the different clones must indeed have originated from different cells.

Complex karyotypes in flow cytometrically DNA-diploid squamous cell carcinomas of the head and neck

In squamous cell carcinoma of the head and neck (SCCHN), DNA ploidy as determined by flow cytometry (FCM) has been found to yield prognostic information but only for tumours at oral sites. Cytogenetic findings have indicated complex karyotype to be a correlate of poor clinical outcome. In the present study, 73 SCCHN were investigated with the two techniques. Aneuploid cell populations were identified in 49 (67%) cases by FCM but in only 21 (29%) cases by cytogenetic analysis. The chromosome index (CI), calculated as the mean chromosome number divided by 46, was compared with the respective DNA index (DI) obtained by FCM in 15 tumours, non-diploid according to both techniques, DI being systematically 12% higher than CI in this subgroup. Eight (33%) of the 24 tumours diploid according to FCM had complex karyotypes, three of the tumours being cytogenetically hypodiploid, three diploid and two non-diploid. The findings in the present study may partly explain the low prognostic value of ploidy status as assessed by FCM that has been observed in SCCHN. In addition, we conclude that FCM yields information of the genetic changes that is too unspecific, and that cytogenetic analysis shows a high rate of unsuccessful investigations, thus diminishing the value of the two methods as prognostic factors in SCCHN.

Smoking tobacco, oral snuff, and alcohol in the etiology of squamous cell carcinoma of the head and neck: a population-based case-referent study in Sweden

BACKGROUND

This case-referent study was conducted to elucidate the role of selected exogenous agents in the etiology of head and neck cancer. The factors studied were tobacco smoking, alcohol intake, the use of moist oral snuff, dietary factors, occupational exposures, and oral hygiene. In this first report, the authors discuss the impact of tobacco smoking, the use of oral snuff, and alcohol consumption.

METHODS

The study base was approximately 2 million person-years at risk and consisted of Swedish males age 40-79 years living in 2 geographic regions during the years 1988-1990. A total of 605 cases were identified in the base, and 756 controls were selected by stratified random sampling from population registries covering the base.

RESULTS

Among those who were tobacco smokers at the time of the study, the relative risk of head and neck cancer was 6.5% (95% confidence interval, 4.4-9.5%). After cessation of smoking, the risk gradually declined, and no excess risk was found after 20 years. The relative risk associated with alcohol consumption of 50 grams or more per day versus less than 10 grams per day was 5.5% (95% confidence interval, 3.1-9.6%). An almost multiplicative effect was found for tobacco smoking and alcohol consumption.

CONCLUSIONS

Tobacco smoking and alcohol intake had a strong interactive effect on the risk of squamous cell carcinoma of the head and neck. Moderate alcohol intake (10-19 grams per day) had little or no effect among nonsmokers. No increased risk was found for the use of Swedish oral snuff.

Early prediction of treatment outcome in head and neck cancer with 2-18FDG PET

The development of alternative treatment regimens in clinical oncology has increased the need for early prediction of cancer therapy outcome. The aim of this study was, early in the treatment phase, to identify patients with advanced head and neck cancer, responding or not responding to initiated therapy. The tumour metabolic rate of glucose (MRgl) examined by 2-18FDG-PET was determined in 17 patients before and after the first weeks of either radiotherapy (16-35 Gy) or one course of combination chemotherapy. Metabolic values uptake values normalized to plasma activity integrals--were correlated to loco-regional outcome, as evaluated 5-6 weeks after completion of treatment. Initial low tumour MRgl (<20 micromol/min/100 g tissue), in primary lesions or regional metastases, predicted a local complete response. When a high initial tumour MRgl was found, the magnitude of the reduction of MRgl in the second PET examination might be an adjunct in predicting local tumour response.

Cytogenetic analysis of inverted nasal papillomas and demonstration of genetic convergence during in vitro passaging

Three inverted nasal papillomas were cytogenetically investigated after short-term culture. Two of the cases were characterized by a single abnormal clone with t(1;8)(p36;q11) and trisomy 7, respectively, whereas the third papilloma showed extreme cytogenetic heterogeneity: of 852 analyzed cells, 329 belonged to 36 unrelated clones, 344 had non-clonal changes, and 179 had a normal chromosome constitution. The polyclonal papilloma was further analyzed during in vitro passage of 3 lines (L1-L3) cultured independently since initiation of the primary cultures and found to have 6, 16 and 6 unrelated clones at analysis of primary cultures. At passage 1, each line was further subdivided into 2 sub-lines (L1A and B, L2A and B, and L3A and B), which were cultured separately until the cells spontaneously stopped dividing. After 4 to 7 passages, each sub-line was dominated (83-98% of the cells) by a single clone. The cell populations that took over the cultures were the same within each set of sub-lines (A and B lines), demonstrating that clonal overgrowth in vitro is not random. The difference in clonal selection among the L1-L3 lines further shows that genetic convergence during in vitro growth in stable conditions is dependent not only on the clones' ability to adapt to the culture conditions, but also on the nature of the neighboring cells with which they collaborate and compete.

Clonal chromosome aberrations accumulate with age in upper aerodigestive tract mucosa

Short-term cultured non-neoplastic upper aerodigestive tract (UAT) mucosa samples from 36 patients with squamous cell carcinoma of the head and neck (SCC) and 53 patients with benign UAT disorders were cytogenetically analyzed. The cell cultures were divided into two series: in series A, cells were cultured in a medium stimulating outgrowth of mesenchymal cells; whereas the cultured cells in series B were of epithelial morphology. Series A was further subdivided into three different age groups (< or = 15 years, 16-59 years, and > or = 60 years) of non-SCC patients and one SCC group. Series B was composed of two groups; one with and one without SCC. Among the non-SCC patients in series A, there was an increase with age in the frequency of cells/sample with numerical and structural chromosomal changes as well as in the incidence of clonal chromosomal aberrations. No differences could, however, be detected between cancer patients and age-matched controls. In series B, the frequency of cells/sample with numerical changes and the incidence of clonal numerical aberrations were significantly higher among SCC patients. Three main conclusions could be drawn. First, the frequencies of clonal and non-clonal chromosome aberrations in UAT mucosa were age dependent. Second, the cytogenetic support for the validity of the field cancerization hypothesis was restricted to increased levels of numerical chromosome changes in epithelial cell cultures from cancer patients. Third, clonal chromosome aberrations, including autosomal and sex chromosome aneuploidies as well as structural rearrangements, are not restricted to neoplastic mucosal cells.

Cancer of the nasopharynx in children and young adults in Scandinavia

Reports have been published indicating an increase in the incidence of cancer in the head and neck, e.g. the tongue, in children and young adults under 40 years of age. In the present study the number of new cases of nasopharyngeal cancer in Scandinavia during the period 1958-1992 was reviewed in the respective national cancer registers. Altogether 3,675 patients were diagnosed with cancer of the nasopharynx. Of these, 371 or 10.1% were under 40 years of age at the time of diagnosis. Within this time period no increase was seen in the relative amount of young among nasopharynx cancer patients in Scandinavia. When considering the whole 35-year period the percentage of patients below 40 years varied between the countries from 7.5% to 18.3%. The majority of the cases in each country occurred in males, both among the young patients as well as in the older age groups. Malignant neoplasms of the nasopharynx are rare in Scandinavia. Both the relative and absolute amount of patients under 40 years of age at the time diagnosis was stable. No difference in the 5-year relative survival rates was seen between the patient group under 40 years when comparing it with all age groups combined.

Correlation between p53 mutation and cyclin D1 amplification in had and neck squamous cell carcinoma

Mutations in the p53 tumour suppressor gene and amplification of the cyclin D1 (CCND1) oncogene have been commonly reported in various malignancies. In the present study of 39 squamous cell carcinomas of the head and neck, p53 mutations were manifest in 11 (28%) of the cases, whereas CCND1 amplification was seen in 6 (16%) of 37 analysed tumours. The 10 mutations occurring in coding sequences of p53 were found in exon 5 (4 cases), exon 6 (3 cases),f and exon 8 (3 cases). No mutation was found in exon 7. Eight of the 10 exon nucleotide substitutions were missense mutations and two were nonsense mutations. All six tumours with CCND1 amplification also had p53 mutations, while an additional five tumours manifested p53 mutations in the absence of CCND1 amplification. There was a statistically significant positive correlation between these two gene alterations. This raises the possibility that mutation of p53 precedes CCND1 amplification in carcinogenesis.

Flow cytometry analysis of malignant tumors of the head and neck--differences between two methods in the recognition of aneuploidy

DNA aneuploidy, which reflects changes in nuclear DNA-content, as determined cytometrically is a candidate prognostic factor in squamous cell carcinoma of the head and neck. The aim of this study was to compare two different preparation methods with respect to their use in detecting aneuploid tumor cell populations in malignant tumors of the head and neck. Fresh frozen tumor material was used. The methods compared were a multistep procedure (A) including fixation of cells and enzymatic treatment, and a one step procedure (B). Both include RNAse and the use of propidium iodide for DNA staining. Forty-seven percent of the tumors were non-diploid according to method A, and 29% according to method B, discordant findings being made in 15 tumors, only two of which were non-SCC. Defining a 'true non-diploid tumor' in this series as a tumor with a DNA index outside the range of diploidy detected either by method A or B, 59% (29/49) of the tumors were non-diploid. The sensitivity was 0.48 (14/29) for method B and 0.79 (23/29) for method A. The striking differences in accuracy between methods A and B emphasize the need of caution when new methods are introduced, and when results obtained with different methods are compared.

Predicting response to therapy of squamous cell carcinoma of the head and neck (review)

The design of treatment for patients with squamous cell carcinoma of the head and neck (SCCHN) is based on prognostic factors, today essentially performance status and TNM status. It becomes increasingly important to optimise treatment and find the appropriate level of treatment and resource consumption for each patient. This can be achieved by means of complementary "biological staging' using predictive factors. A predictive factor contains prognostic information but can also be used to choose between alternative treatments. Candidate variables for prediction of the outcome of chemotherapy are tumour ploidy status, the level of circulating C1q-complexes, the level of p53 expression, and resistance/sensitivity measured by in vitro assays. Several variables and assays capable of predicting response to radiotherapy have been proposed, e.g. the surviving fraction 2 Gy (SF2), potential tumour doubling time (Tpot), and the micronucleus assay. As none of these have yet proved to be of clinical value in a prospective randomised trial, continued studies are well worthwhile.

Metoclopramide as a modulator of cisplatin: effects on pharmacokinetcs and cisplatin-DNA adducts in tumor and normal tissue

The antiemetic drug metoclopramide (MCA) has previously been shown to cause DNA damage, to inhibit DNA repair and to enhance the effect of the chemotherapeutic agent cisplatin. Cisplatin acts by binding to DNA and thus forming cisplatin-DNA adducts. The present study was designed to investigate whether MCA affects the pharmacokinetics of cisplatin and the levels of cisplatin-DNA adducts in tumor and kidney. The effect on kidney is of special interest since cisplatin is highly nephrotoxic. Nude mice with xenografted squamous cell carcinoma where injected with cisplatin 5 mg/kg i.p. alone or in combination with MCA 2 mg/kp i.p. MCA was given 8 h after cisplatin. Total platinum was measured in serum and cisplatin-DNA adducts were analyzed in tumor and kidney with quantitative immunohistochemistry at 1, 9 and 24 h after cisplatin administration. The efficacy after treatment with cisplatin, MCA or cisplatin + MCA was studied in terms of tumor size measurements during 3 weeks following treatment and our previous observation that MCA enhances the cisplatin cytotoxicity was confirmed. The addition of MCA to cisplatin resulted in a slight increase in serum-platinum concentrations at 9 h and increased levels of adducts in tumors at 24 h. There was a tendency, however, not statistically significant, for increased adducts also in kidney. Thus, our findings may indicate that the sensitization of MCA on the cytotoxicity of cisplatin is mediated by increased formation, maybe accompanied by inhibited repair, of cisplatin-DNA adducts.

Clonal chromosome abnormalities in two chemodectomas

Short-term cultures from two histologically benign chemodectomas, one from the carotid body and one from the vagal nerve, were analyzed cytogenetically. The former had a small abnormal clone with the karyotype 46,XX,t(3;19)(q21;q13),t(12;15) (p13;q12-14), whereas the majority of the cells from the latter tumor displayed two related abnormal clones: 46,XY,i(I)(q10)/ 46,iderm,add(2)(q37). The findings add to the evidence that chemodectomas are heterogeneous neoplasms and suggest that the heterogeneity may possibly be associated with the site of origin.

Mandibular reconstruction by secondary reimplantation of resected segments: a preliminary report

This paper presents a new method of reconstructing the mandible after ablative surgery for cancer. This method uses autogenous grafts consisting of the respected part of the mandible, which is hollowed out, defatted in chloroform/methanol, sterilized with ethylene oxide, irradiated with beta-radiation (dose 25 kGy), and stored for 7-10 months. At reimplantation, they were filled with compressed, autogenous, particulate cancellous bone. All grafts took, and four of six host-graft junctions healed.

Nonrandom chromosome abnormalities in short-term cultured primary squamous cell carcinomas of the head and neck

We report the finding of clonal chromosome abnormalities in short-term cultures from 44 squamous cell carcinomas of the head and neck region. Eleven tumors had gain or loss of the Y chromosome, sometimes one clone with +Y and another with -Y, as the sole anomaly, whereas the remaining 33 all carried structural rearrangements and usually were cytogenetically complex with multiple aberrations. The chromosomal bands most frequently involved were, in decreasing order of frequency, 8p11-q11, 1p11-q11, 3p11-q11, 11q13, 13p11-q11, 1p13, 5p11-q11, 7p11-q11, 15p11-q11, and 14p11-q11. Almost one-half of the breakpoints were located in centromeric or juxtacentromeric bands. Recurrent aberrations included i(8q), i(5p), i(1q), del(3)(p11-12), del(5)(p11), t(1;1)(p13;q25), and der(14;15)(q10;q10). To see whether the karyotypic features of head and neck squamous cell carcinoma differ depending on exact tumor site, we added to the present series our previously published 23 karyotypically abnormal head and neck squamous cell carcinomas that had been cultured in the same way as the tumors of the present series. In the ensuing correlation analysis, tumors of the oral cavity and oropharynx and hypopharynx were found to share many features: highly complex karyotypes were frequent, often containing isochromosomes such as i(8q) and i(5p), and also rearrangements of 11q13 (often as homogeneously staining regions) and loss of genetic material from the short arms of chromosomes 3, 13, 14, and 15 were repeatedly seen. Laryngeal carcinomas, on the other hand, often had simple karyotypic changes.

Tumor angiogenesis and prognosis in squamous cell carcinoma of the head and neck

BACKGROUND

The progression of tumor growth requires the recruitment of new blood vessels. It has been suggested that the degree of neovascularization would correlate with clinical prognosis. The purpose of the present study was to ascertain whether tumor vascularization correlated with clinical outcome in cases of primary squamous cell carcinoma of the head and neck (SCCHN).

METHODS

In tumor biopsies from 48 patients, microvessel density was determined by immunohistochemistry based on polyclonal antibodies against factor VIII related endothelial antigen. Computerized image analysis was used to evaluate the staining intensity per histologic area. The degree of staining was quantitated and expressed as microvessel density, low and high microvessel density subgroups being compared with regard to survival.

RESULTS

Median survival was 10 months in the subgroup with very low microvessel density scores, as contrasted to 69 months in the remainder with high scores (p = 0.08). Neither the patient's age, TNM status, clinical stage, nor histologic grade was related to microvessel density. Among the patients who eventually died of SCCHN (n = 23), there was a subgroup of patients with complete response to radiotherapy. This subgroup had significantly higher microvessel density and longer survival than did the patients who responded poorly or not at all to radiotherapy.

CONCLUSION

The findings suggest that in SCCHN the degree of vascularization might be used as a predictor of response to radiotherapy.

Pre versus post-operative radiotherapy of resectable squamous cell carcinoma of the head and neck

The literature on pre-operative radiotherapy (RT) vs. post-operative RT in patients with advanced, resectable squamous cell carcinoma of the head and neck is reviewed and the theoretical arguments for and against the two different modalities discussed. It was possible to identify eleven reports published during the last four decades (1965-91) evaluating different aspects of pre- vs. post-operative RT given at comparable dose levels. Two reports were of prospective, randomised clinical studies and nine of retrospective comparisons. Together, the eleven studies comprised 1,358 patients (326 in prospective studies). The bulk of the evidence clearly suggests post-operative loco-regional control to be superior to pre-operative RT. However, this seems to be offset by the subsequent development of distant metastases or metachronous tumours.

Karyotypic features of malignant tumors of the nasal cavity and paranasal sinuses

Cytogenetic analysis of short-term cultures from 6 tumors of the nasal cavity and paranasal sinuses--one esthesioneuroblastoma, 2 adenocarcinomas and 3 squamous-cell carcinomas (SCC)--revealed clonal chromosome aberrations in all cases. The esthesioneuroblastoma had a complex hyperdiploid karyotype. None of the aberrations was similar to those previously described in short-term cultures or established cell lines from esthesioneuroblastomas. The 2 adenocarcinomas had complex karyotypic changes, which in both cases included rearrangements of bands 9p22 and 14q11. One SCC had 5 unrelated pseudodiploid clones, 1 displayed a highly complex karyotype, including rearrangement of band 11q13, and 1 had simple karyotypic changes with loss of 6q material and gain of 3q. These findings are similar to those described in head-and-neck SCC at other sites.

Tetraploidization and progressive loss of 6q in a squamous cell carcinoma of the parotid gland

Cytogenetic analysis of short-term cultures from a squamous cell carcinoma (SCC) of the parotid gland revealed one clone with loss of the Y chromosome only, as well as three related subclones: 91,XXYY,add(6)(q21), -11,t(11;22)(q13;q11),ins(15;?)(q22;?)[cp5+ ++]/91,XXYY,add (6)(q21), -11,add(11)(p11), ins(15;?)(q22;?),der(22)t(11;22)(p11;q11)[2]/91,XXYY,add(6)(q11), -11,add(11)(p11),ins(15;?)(q22;?),der(22) t(11;22)(p11;q11) [cp4]. The finding of only one copy of all structurally rearranged chromosomes in a near-tetraploid karyotype indicates that tetraploidization was an early event in tumorigenesis. Rearrangements, in particular deletions, of 6q have previously been associated with adenoid salivary gland malignancies. Our finding of progressive 6q loss with clonal evolution, combined with the fact that 6q deletions were also seen in the two previously reported SCCs of the salivary glands, indicate that loss of genetic information from this chromosome arm is characteristic for most types of salivary gland carcinomas, irrespective of their histologic differentiation.

Radiation effects on S-phase duration, labelling index, potential doubling time and DNA distribution in head and neck cancer xenografts

The effect of irradiation on S-phase duration (Ts), labelling index (LI), potential doubling time (Tpot), and cell cycle phase distributions was determined by DNA flow cytometry in xenografted human squamous cell carcinoma of the head and neck (SCCHN). Tumours were treated with a single dose of 3 Gy, and excised at intervals over a 90-h period. Six hours before each excision the tumours were labelled in vivo with bromodeoxyuridine (BrdUrd). Although the growth rate of irradiated tumours was comparable with that of untreated controls, analysis of BrdUrd uptake revealed a transient reduction of LI and a prolongation of Ts in irradiated tumours. Maximum mean Tpot was 931 days in irradiated tumours as compared to 13 days in untreated controls. The variations in Ts, LI and Tpot all occurred within the first hours after irradiation; during the remainder of the observation time, the values of the variables did not differ from those of untreated controls. In irradiated tumours the distribution of cells according to DNA content changed significantly on three occasions during the observation period: 1) Parallel to the initial lowering of LI and prolongation of Ts there was a transient increase in the proportion of cells in G0/G1 and a decrease in the proportion of cells in S and G2; 2) At 18 h, the most pronounced cell cycle phase redistribution occurred when the G0/G1 fraction decreased and the S and G2 phase fractions increased; 3) At 66 h (i.e., approximately one cell cycle later), the pattern was the same as that after 18 h. The findings suggest that the transient prolongation of DNA replication seen in SCCHN cells immediately after a single radiation dose is a symptom of DNA damage inflicted during late G1 or early S-phase, and that this disturbance in DNA synthesis is associated with the subsequent accumulation of cells in G2 phase.

Characteristic karyotypic features in lacrimal and salivary gland carcinomas

Short-term cultures from 12 non-squamous cell carcinomas (NSCCs) of the head and neck were cytogenetically investigated. Three tumours were acinic cell carcinomas, two adenoid cystic carcinomas, three mucoepidermoid carcinomas, two carcinomas in pleomorphic adenoma, and two adenocarcinomas. Clonal chromosome aberrations were detected in all but one adenocarcinoma. Including our data, a total of 40 head and neck NSCCs with clonal aberrations have been described. Deletions of the long arm of chromosome 6 are the most common aberrations (11/40 cases); they have been detected in all types of NSCC except carcinoma in pleomorphic adenoma. Two aberrations seem to be closely associated with tumour type: t(6;9)(q21-24;p13-23), which has been seen in three of 11 adenoid cystic carcinomas (in two as the sole aberration), and structural rearrangements of 8q12-13, which have been detected in three of four carcinomas in pleomorphic adenoma.

Biochemical modulation of chemotherapy and radiotherapy in head and neck cancer

In order to improve the treatment of advanced H&N cancer we must consider to adopt new strategies as: new/better cytostatic agents; new combinations of present cytostatic agents and; potentiation of radiotherapy and cytostatic agents by biochemical modulation, which we define as potentiation of therapy by non-chemotherapeutic agents. The list of agents that can potentiate chemotherapy or circumvene resistance is comprehensive. Most of the data are derived from in vitro studies. Much attention has been given to the fact that calcium channel blocker (CCB) agents can circumvene the multi-drug resistance (MDR) phenotype. Cisplatin, 5-fluorouracil, bleomycin and methotrexate, used in the treatment of head and neck cancer, are not part of the MDR phenotype. Still there are a few interesting reports indicating that CCB's could enhanced the antitumour actions of cisplatin, and that this interaction may be: (a) very specific; (b) unique to each species of CCB and (c) is independent of their binding affinity and classical function as inhibitors of the voltage sensitive calcium channels. Metoclopramide (MCA) is a structural analogue of procainamide used worldwide for preventing nausea and vomiting. It has structural resemblance to some of the known inhibitors of the DNA associated enzyme poly ADPRT such as benzamide. Benzamide is however rather toxic. MCA has been shown to enhance the effect of CDDP in vivo as well as in permeabilized cells in vitro, indicating that the DNA damaging effect of MCA is not dependent on cytoplasmatic enzymes or messenger systems. Radiobiologists have pointed out important biologic characteristics about tumour tissue such as hypoxia in relation to tumour radiosensitivity. Nicotinamide can effect tumour radiosensitivity in vivo. Comparing the response of mice in skin and tumour under different gas breathing regimens, a considerable therapeutic gain has been demonstrated for oxygen and carbon dioxide (95% O2 + 5% CO2) breathing mice. The effect of ionizing radiation (RT) on xenografted squamous cell carcinoma can also be enhanced by MCA. The optimal treatment interval is MCA given one hour before RT, which is in concordance with the hypothesis that MCA has to be present at the site of injury when RT is given in order to interact with repair mechanisms. We could not in conventional mice detect any MCA induced enhancement of either acute skin reaction or in LD50/30 after whole body irradiation, which indicates a potential therapeutic gain using MCA in a clinical setting. The above discussed interactions between biochemical modulators and chemo-/radio-therapeutic agents serve to illustrate the fruitful concept of biochemical potentiation of cytotoxicity.(ABSTRACT TRUNCATED AT 400 WORDS)

DNA analysis as a predictor of the outcome of induction chemotherapy in advanced head and neck carcinomas

We investigated whether flow cytometric DNA index and/or ploidy status are predictors of response to chemotherapy and survival. Fifty consecutive patients with previously untreated locally advanced squamous cell carcinomas of the head and neck received induction chemotherapy consisting of three courses of cisplatin (100 mg/m2) and a subsequent 120-hour infusion of fluorouracil (1000 mg/m2 per 24 hours) repeated every 3 weeks. Chemotherapy was followed by radiotherapy to a median target dose of 65 Gy and subsequent surgery for residual tumor. The median observation time was 27 months (range, 24 to 57 months). Flow cytometric DNA analysis was based on formalin-fixed and paraffin-embedded tissue from pretreatment tumor biopsy specimens. Complete response after induction chemotherapy was achieved in only 12% (2/17) of patients with diploid tumors compared with 39% (13/33) of those with nondiploid tumors. Among patients with nondiploid tumors, DNA index was higher for those responding to chemotherapy compared with the nonresponders. Complete response to chemotherapy was apparently a prerequisite for survival in the nondiploid group. Of the patients not responding to chemotherapy but responding to subsequent radiotherapy, survival was better among those with diploid tumors than among those with nondiploid tumors.

Chromosome abnormalities in eighty-three head and neck squamous cell carcinomas: influence of culture conditions on karyotypic pattern

Short-term cultures from 115 squamous cell carcinomas (SCC) of the head and neck were cytogenetically investigated. Thirty-six of the tumors have been reported previously, whereas 79 are new cases. The material was divided into two series based on the medium used. The 80 tumors of series I were cultured in RPMI 1640 supplemented with fetal calf serum, glutamine, antibiotics, insulin, cholera toxin, and epidermal growth factor. The 35 tumors of series II were cultured in a chemically defined, serum-free medium with a low calcium concentration, MCDB 153, which stimulates epithelial growth while inhibiting fibroblasts. A total of 83 tumors with clonal karyotypic abnormalities were detected in the two series. Series II had a higher proportion of tumors with complex karyotypic changes than series I (43% versus 15%), a lower proportion of tumors with pseudo- or neardiploid clones characterized by simple rearrangements (3% versus 34%), and a lower frequency of unrelated clones (3% versus 24%), indicating that the different culture conditions favored growth of different cell populations. Except for rearrangements of 1p22, which were mainly found in series I, the distribution of breakpoints in structural aberrations was similar in the two series and clustered to several chromosomal bands or regions, in particular 11q13, 1p22, 1p11-12, 3p11-q11, 5q13, 1q25, 15q10, and 8q10. Unbalanced structural aberrations were more common in series II, frequently leading to loss of segments from chromosome arms 3p, 7q, 8p, 11q, 13p, 14p, and 15p, whereas gain of genetic material often involved chromosome arms 1q, 3q, 8q, and 15q.