Flow cytometric analysis of squamous cell carcinoma of the tongue

Immunohistochemical estimation of cell cycle phase in laryngeal neoplasia

We previously developed an immunohistochemical method for estimating cell cycle state and phase in tissue samples, including biopsies that are too small for flow cytometry. We have used our technique to examine whether primary abnormalities of the cell cycle exist in laryngeal neoplasia. Antibodies against the markers of cell cycle entry, minichromosome maintenance protein-2 (Mcm-2) and Ki67, and putative markers of cell cycle phase, cyclin D1 (G1-phase), cyclin A (S-phase), cyclin B1 (G2-phase) and phosphohistone H3 (Mitosis) were applied to paraffin-embedded sections of normal larynx (n=8), laryngeal dysplasia (n=10) and laryngeal squamous cell carcinoma (n=10). Cells expressing each marker were determined as a percentage of total cells, termed the labelling index (LI), and as a percentage of Mcm-2-positive cells, termed the labelling fraction (LF). The frequency of coexpression of each putative phase marker was investigated by confocal microscopy. There was a correlation between Mcm-2 and Ki67 LIs (ρ=0.93) but Mcm-2 LIs were consistently higher. All cells expressing a phase marker coexpressed Mcm-2, whereas Ki67 was not expressed in a proportion of these cells. The putative phase markers showed little coexpression. Labelling index values increased on progression from normal larynx through laryngeal dysplasia to squamous cell carcinoma for Mcm-2 (P=0.001), Ki67 (P=0.0002), cyclin D1 (P=0.015), cyclin A (P=0.0001) and cyclin B1 (P=0.0004). There was no evidence of an increase in the LF for any phase marker. Immunohistochemistry can be used to estimate cell cycle state and phase in laryngeal biopsies. Our data argues against primary cell cycle phase abnormalities in laryngeal neoplasia.

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.

Squamous carcinoma of the tongue: review

Carcinoma of the tongue is a common condition treated by oral and maxillofacial surgeons. The tongue is a complex anatomical site at the entrance of the oropharynx, bounded by the floor of mouth and lingual mandibular cortex; its form and mobility are crucial for efficient swallowing; speech, and the appreciation of taste. Single and multiple treatments have been used, but the tongue remains a difficult area to assess and treat. In this paper, we have attempted to review some of the papers published over the last 20 years with particular reference to prognosis and functional outcome. We have dealt exclusively with squamous cell carcinoma of the tongue and its management by surgery, radiotherapy, brachytherapy, photodynamic therapy, and chemotherapy.

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.