Flow cytometric analysis of nuclear DNA content in tongue squamous cell carcinoma: relation to cervical lymph node metastasis

Inherent variability of cancer-specific aneuploidy generates metastases

Background

The genetic basis of metastasis is still unclear because metastases carry individual karyotypes and phenotypes, rather than consistent mutations, and are rare compared to conventional mutation. There is however correlative evidence that metastasis depends on cancer-specific aneuploidy, and that metastases are karyotypically related to parental cancers. Accordingly we propose that metastasis is a speciation event. This theory holds that cancer-specific aneuploidy varies the clonal karyotypes of cancers automatically by unbalancing thousands of genes, and that rare variants form new autonomous subspecies with metastatic or other non-parental phenotypes like drug-resistance – similar to conventional subspeciation.

Results

To test this theory, we analyzed the karyotypic and morphological relationships between seven cancers and corresponding metastases. We found (1) that the cellular phenotypes of metastases were closely related to those of parental cancers, (2) that metastases shared 29 to 96% of their clonal karyotypic elements or aneusomies with the clonal karyotypes of parental cancers and (3) that, unexpectedly, the karyotypic complexity of metastases was very similar to that of the parental cancer. This suggests that metastases derive cancer-specific autonomy by conserving the overall complexity of the parental karyotype. We deduced from these results that cancers cause metastases by karyotypic variations and selection for rare metastatic subspecies. Further we asked whether metastases with multiple metastasis-specific aneusomies are assembled in one or multiple, sequential steps. Since (1) no stable karyotypic intermediates of metastases were observed in cancers here and previously by others, and (2) the karyotypic complexities of cancers are conserved in metastases, we concluded that metastases are generated from cancers in one step – like subspecies in conventional speciation.

Conclusions

We conclude that the risk of cancers to metastasize is proportional to the degree of cancer-specific aneuploidy, because aneuploidy catalyzes the generation of subspecies, including metastases, at aneuploidy-dependent rates. Since speciation by random chromosomal rearrangements and selection is unpredictable, the theory that metastases are karyotypic subspecies of cancers also explains Foulds’ rules, which hold that the origins of metastases are “abrupt” and that their phenotypes are “unpredictable.”

DNA ploidy, proliferative capacity and intratumoral heterogeneity in primary and recurrent head and neck squamous cell carcinomas (HNSCC) – Potential implications for clinical management and treatment decisions

Despite new diagnostic and therapeutic strategies (combined radiochemotherapy, EGFR antibody Cetuximab), the prognosis of head and neck squamous cell carcinoma (HNSCC) is still poor and more information regarding prognosis is essential to establish earlier and better treatment options. To elucidate the role of DNA ploidy and cellular proliferation, resected tumors of 48 patients with primary or recurrent HNSCC were analyzed by flow cytometry and in vitro-5-bromodeoxyuridine incorporation (BrdU). The results were compared with histopathological findings such as tumor size, lymph node involvement and tumor differentiation. To assess the influence of intratumoral heterogeneity of these biological parameters, multiple biopsies (>3) were analyzed by flow cytometry and BrdU-incorporation in 12 larger (>4 cm diameter) tumors. BrdU-labeling index (LI%) was significantly higher in aneuploid HNSCC and correlated significantly with poor histologic differentiation of the analyzed tumor tissues (P<0.001). Furthermore, a trend for higher LI% in nodal positive tumors was observed. Aneuploid HNSCC showed significantly more often tissue dedifferentiation (P=0.049) and in most cases an advanced tumor stage, especially in tumors with biclonal cell lines. Lymph node involvement was also seen more often in aneuploid and undifferentiated tumors. As in aneuploid tumors recurrent HNSCC showed in most cases a higher LI% and poor tissue differentiation, but as a result of the small collection of samples there was no correlation between aneuploidy and tumor recurrence. To proof the robustness of the acquired data and to estimate the influence of intratumoral heterogeneity to ploidy and LI% multiple biopsies were analyzed in larger tumors. Using a specific statistical algorithm a secure estimation of ploidy and LI% was possible by a single biopsy in these tumors. These findings indicate aneuploidy and proliferative activity as important findings for malignant progression in HNSCC. An estimation of these biological parameters may be useful for identification of patients with high risk for lymph node involvement or tumor recurrence and pre-treatment can be performed by a single biopsy. As a conclusion, these patients may benefit from more aggressive treatment.

Staging of the neck in patients with head and neck squamous cell cancer: Imaging techniques and biomarkers

Regional metastasis is an important factor in the treatment and prognosis of head and neck cancer patients. Current treatment strategies rely on staging based on the still limited accuracy of imaging techniques to detect regional metastases. If more certainty about the nodal status could be attained, treatment strategies concerning the neck could be better adjusted to the individual patient. The continuing improvement of established imaging techniques and the introduction of new imaging modalities will add to better staging. Moreover, the additional use of biomarkers studied on a protein, RNA or DNA level may provide even better information about the chance of occult nodal metastasis in head and neck cancer patients.

DNA ploidy status as a prognostic marker and predictor of lymph node metastasis in laryngeal carcinoma

In patients with laryngeal carcinoma, nodal metastasis, recurrence after radiotherapy, and prognosis are important factors in clinical decision-making. Parameters such as tumor stage are considered insufficient for predicting these important items. The DNA ploidy status of the tumor may be a useful additional marker. The DNA ploidy status of 38 laryngeal cancers was determined by flow cytometry. Correlations were studied with TNM stage, differentiation, survival rate, relapse risk, recurrence after radiotherapy, and nodal metastasis. A positive correlation of DNA ploidy status with the development of lymph node metastases was found for diploid and peridiploid versus aneuploid tumors (DNA index, <1.4 versus > or = 1.4; p = .007). No correlation was found between ploidy status and recurrence after radiotherapy. The overall survival rate (p = .01), but not the disease-specific survival rate or the relapse risk, showed a correlation with the ploidy status. The DNA ploidy status may be a useful marker for metastatic behavior in head and neck squamous cell carcinoma and may therefore be helpful in decision-making concerning elective treatment of the neck.

Can flow cytometrically determined DNA ploidy and S-phase fraction predict regional metastasis in squamous cell carcinoma of the oral cavity?

BACKGROUND

The value of flow cytometric analysis of DNA ploidy and S-phase fraction (SPF) as an indicator of regional metastasis in oral cancer is currently being debated. Intratumoral heterogeneity makes this problem complex.

METHODS

Intratumoral DNA ploidy heterogeneity and intratumoral SPF variation were examined using multiple specimens from 31 surgically resected specimens taken from patients with oral cancer without preoperative therapy. Flow cytometric analysis of single biopsy specimens from 79 patients with oral cancer was also undertaken to ascertain their value as indicators of regional metastasis.

RESULTS

Forty-five percent (14 of 31) of tumors showed intratumoral ploidy heterogeneity. Intratumoral SPF variation in the 31 tumors ranged from 0.2% to 6.9% (mean, 3.3%). Multivariate analysis showed that a SPF greater than 27% was the most important parameter for predicting regional metastasis.

CONCLUSIONS

DNA ploidy is heterogeneous within a tumor, whereas SPF is relatively stable and can be correlated with regional metastasis in oral cancer.

Improved prediction of metastasis in tongue carcinomas, combining vascular and nuclear tumor parameters

BACKGROUND

Predicting the presence of metastasis, based on tumor or tumor-related characteristics is of utmost importance. The authors studied the significance of tumor DNA features and tumor-related angiogenesis to predict the occurrence of metastasis in squamous cell carcinomas (SCCs) of the tongue.

METHODS

Paraplast blocks from resection specimens of 20 metastasized and 20 nonmetastasized SCCs of the tongue with a minimum follow-up of 24 months were used. Tissue sections were stained with anti-CD34 monoclonal antibodies for vessel visualization, and according to Feulgen to stain DNA. Using image analysis, data from both stainings were computed for each of the 40 carcinomas. A logistic regression model to predict the presence of metastasis, based on vascular and nuclear morphology features, was developed.

RESULTS

The intratumor variation of chromatin condensation and the percentage vessels smaller than 5 microm in diameter were selected for the model. The model correctly predicted metastasis in 90% of patients and excluded metastasis correctly in 75% of nonmetastasized tumors. Taking into account the prevalence of metastasis in SCC of the tongue of between 30% and 60%, this means a predictive value for a negative outcome of between 95% and 83%.

CONCLUSIONS

The proposed model shows an improvement of predictive values compared with previous models with single parameters. Therefore, a multiparameter model appears to predict the multiparameter process of metastasis better.

The significance of DNA flow cytometry in predicting survival and delayed clinical manifestation of occult lymph node metastasis to the untreated neck in patients with oral squamous cell carcinoma

A total number of 116 clinically neck-negative patients with squamous cell carcinoma of the oral cavity who underwent radical primary tumour surgery without simultaneous neck treatment were entered into this prospective study. The 5 year overall survival rate was 87% for patients with flow cytometrically diploid tumours and 58% for the aneuploid group (P < 0.05). By multivariate survival analysis, tumour stage (P < 0.05) and DNA ploidy (P < 0.05) were significantly associated with the outcome. The cumulative 3 year rate of delayed clinical manifestation of lymph node metastasis to the previously untreated neck was 12.6% for patients with flow cytometrically diploid tumours and 41.3% for the aneuploid group (P < 0.01). By multivariate analysis, the DNA ploidy status of the primary tumour was the only factor among tumour stage, localization and degree of histological differentiation predictive of occult metastasis development (P < 0.05). Also, patients with T1 tumours who frequently are not considered to benefit from elective neck dissection were at high risk of subclinical lymph node involvement if the primary tumours were aneuploid (47%), whereas only 10% of the diploid T1 sample showed occult neck disease. Particularly in patients with less extensive oral carcinomas, DNA aneuploidy is therefore an important decisive factor in elective neck dissection.

Nuclear DNA content and p53 overexpression in stage I squamous cell carcinoma of the tongue compared with advanced tongue carcinomas

AIMS

To evaluate the predictive value of the nuclear DNA content (image cytometry) and p53 overexpression (immuno-histochemistry using antibody CM-1) in uniformly treated stage I carcinomas of the mobile tongue. Also, to compare stage I carcinomas with advanced tongue carcinomas (stages II-IV).

METHODS

Archival formalin fixed, paraffin wax embedded tumour specimens from 54 patients with stage I squamous cell carcinoma and 37 patients with advanced squamous cell carcinoma were analysed. Mean follow up time of the stage I carcinomas was 71 months (median, 62.5; range, 6-175).

RESULTS

Twenty three patients (stage I) had recurring disease: 10 had local recurrence (in the tongue) and 13 had regional recurrence (cervical metastases). Locally recurring stage I carcinomas had a more pronounced DNA deviation than the other stage I carcinomas and this degree of deviation was comparable with the DNA content of advanced carcinomas. Stage I carcinomas that developed regional recurrences overexpressed p53 more frequently. In Cox multivariate regression analysis of time to recurrence, DNA deviation was a significant parameter in tumours that recurred locally (p = 0.032). p53 overexpression was the only parameter close to significance for regional recurrence (p = 0.065).

CONCLUSIONS

Nuclear DNA content and p53 immunostaining are of value for the prediction of recurrence of stage I squamous cell carcinomas of the mobile tongue. Stage I tongue carcinomas that are prone to local recurrence show the same DNA content as do advanced tongue carcinomas.

Representativity of incisional biopsies for the assessment of flow cytometric DNA content in head and neck squamous cell carcinoma

DNA flow cytometry studies of squamous cell carcinoma of the head and neck have shown that patients with diploid tumours have favourable prognoses, whereas the outcomes of those with DNA aneuploid tumours are poor. DNA flow cytometry is therefore increasingly used as an integral part of diagnostic procedures. To evaluate how representative biopsies predict the DNA ploidy of oral carcinomas, incisional biopsies taken pretherapeutically from 256 tumours were compared with the corresponding surgical resection specimens. Sixty-six tumours exclusively displayed cells with flow cytometrically diploid DNA content in both the biopsy and the subsequent resection specimen, while 182 carcinomas expressed DNA aneuploid tumour cell lines in matched samples. There were only 8 tumours (3.1%) with heterogeneity in the DNA ploidy status between the biopsy and the resection specimen. These results emphasise the usefulness of incisional biopsies to reliably prognosticate the DNA ploidy status of oral carcinomas.

Can we detect or predict the presence of occult nodal metastases in patients with squamous carcinoma of the oral tongue?

BACKGROUND

When to do a neck dissection as part of the surgical treatment for a patient with squamous carcinoma of the oral tongue is controversial, particularly when the primary can be resected without entering the neck. If the patient who is at high risk for having occult nodal disease in the neck can be identified, node dissection with the glossectomy could be justified. To better identify patients for this procedure, we correlated various tumor and patient factors along with preoperative diagnostic studies with the presence or absence of pathologically positive nodes in a group of patients who underwent node dissection.

METHODS

Ninety-one previously untreated patients with biopsy-proved squamous carcinoma of the oral tongue were prospectively studied. All patients had a glossectomy and neck dissection as their initial treatment. The pathology findings (ie, lymph nodes with squamous cancer) were correlated with many preoperative and intraoperative factors, and a statistical analysis was made.

RESULTS

The use of computed tomography and ultrasound was not better than the clinical examination in determining the presence or absence of nodal metastases. The best predictors were depth of muscle invasion, double DNA aneuploidy, and histologic differentiation of the tumor.

CONCLUSIONS

All patients with stage T2-T4 squamous cancers of the oral tongue should have an elective dissection of the neck. Patients with T1N0 cancer who have a double DNA-aneuploid tumor, depth of muscle invasion > 4 mm, or have a poorly differentiated cancer should definitely undergo elective neck dissection. Ultrasound and computed tomography are of little value in predicting which patients have positive nodes.

The value of DNA flow cytometry in predicting the development of lymph node metastasis and survival in patients with locally recurrent oral squamous cell carcinoma

BACKGROUND

DNA flow cytometry studies of squamous cell carcinoma of the head and neck have shown that patients with diploid tumors have favorable prognoses, whereas the outcomes of those with, aneuploid tumors are poor. This study was conducted to examine the importance of DNA ploidy in patients with locally recurrent oral carcinoma.

METHODS

DNA flow cytometry was performed on 93 primary oral carcinomas and their subsequent recurrences.

RESULTS

Eight patients with diploidy of both the primary tumor and the recurrence never developed lymph node metastasis. The 5-year overall survival rate of this group was 87%. For 80 aneuploid primary carcinomas, recurrences developed that were also aneuploid. Only 31% of these patients were 5-year survivors (P < 0.001). Lymph node metastasis at presentation was found in 55% of this group, whereas 13% of initially lymph node negative patients presented with regional disease at second surgery. Five of 13 diploid primary tumors recurred with aneuploid cell lines. Three of these five patients died, two with regional metastasis. The 5-year survival rate of patients with aneuploid recurrences who were never afflicted with lymph node involvement (41%) was better (P < 0.05) than the 5-year survival rate of those with metastasis at presentation or at second surgery (26%).

CONCLUSIONS

The excellent prognosis of patients with diploid primary tumors can be reestablished by treating local recurrences with radical surgery, if the surgery is performed before aneuploid cell lines have emerged. It appears that aneuploid tumor cell lines acquire unique properties that make them capable of invasion and metastasis.

DNA ploidy analysis of squamous cell carcinomas of the oral and maxillofacial region: clinical and pathologic correlations

DNA ploidy was investigated in 61 specimens obtained from 25 patients with squamous carcinoma of the oral and maxillofacial region. Biopsy specimens of normal tissue surrounding the tumor were also obtained in six patients. Single-cell suspensions for flow cytometric analysis were prepared. The DNA ploidy and histogram were calculated and compared with the histologic grade, presence of lymph node metastases, and course of the disease. The ploidy of the main stemline was peridiploid in 17 carcinomas, hyperdiploid in three, and aneuploid in five. Histologic grade but not nodal involvement was associated with the ploidy of the main stemline. Of 15 multisampled carcinomas 13 showed constant DNA ploidy and histogram classification. In the other two major changes in DNA ploidy (from peridiploid to hyperdiploid in the first and from peridiploid to aneuploid in the second) were found. Survival information was available for 24 patients. Ploidy values higher or lower than 2.5 c were strongly predictive of both overall (p < 0.001) and relapse-free survival (p < 0.001). The lymph node status proved a powerful prognostic indicator (p = 0.014) but was not related to the relapse-free time of survival. Multiparametric evaluation of survival revealed an independent role of both DNA ploidy and nodal involvement in the prognosis of squamous carcinoma of the oral and maxillofacial region.

The implication of DNA content and S-phase fraction in oral carcinomas with and without metastasis

Flow cytometry DNA analysis was performed on fresh tissue samples of 90 primary lesions and 32 metastatic lymph nodes of squamous cell carcinomas of the oral cavity and related regions to elucidate the characteristics of tumors with metastatic potency. The incidence of aneuploidy for carcinomas with metastasis was 67%, which was significantly higher than the 44% of carcinomas without metastasis, and aneuploid carcinomas (39%) had a higher tendency to metastasis than diploid carcinomas (20%). The incidence of aneuploidy and metastasis was related to the T classification, the degree of differentiation, and the histologic grade of malignancy. The incidence of aneuploidy and mean DNA index of metastatic lesions were 31% and 1.12, respectively, and the values were significantly lower than the 67% and 1.30 of the corresponding primary lesions. The results indicate that the chance of evolution of metastatic cell lines is higher in aneuploid carcinomas than diploid carcinomas, possible because the former is more heterogeneous than the latter, but most of the cell lines causing lymph-node metastasis are diploid cell lines. Metastatic lesions had a lower S-phase fraction than primary lesions, indicating that a high S-phase fraction does not always reflect the presence of metastatic cell lines.

Quantitative multivariate analysis of myoepithelioma and myoepithelial carcinoma

The nuclear DNA content and morphologic data of 30 surgical samples (eight normal parotid gland, 12 myoepithelioma, and 10 myoepithelial carcinoma) were analyzed by the IBAS II analysis system. The results suggest that there are relationships between tumor ploidy distribution and prognosis, and that correct pathologic diagnosis can be obtained by the IBAS image system.