Thirty-four mucoepidermoid carcinomas were studied retrospectively with regard to histological and clinical parameters. In 28 of the tumors DNA patterns were also assessed using flow cytometry. Twenty-two of the 28 tumors (79%) were DNA diploid and 6 (21%) DNA aneuploid. Two tumors (7%) showed intratumoral DNA as indicated by different stemlines in specimens investigated from different parts of the tumor. DNA ploidy correlated significantly with cervical lymph node status (P < 0.01), but not with tumor size or histological grade. The mean S-phase value was 2.7% and was significantly higher in aneuploid samples than in diploid ones (P < 0.05). The recurrence rate was significantly lower for patients with stage I and II tumor compared with those with stage III and IV disease (P < 0.01). Five aneuploid tumors showed significantly higher recurrence rates (5/6) than the diploid ones (1/22) (P < 0.01). In univariate analysis for survival, only N stage tumor (P < 0.05) and tumor DNA ploidy (P < 0.0003) had significant prognostic influence. Thus, DNA ploidy seems to be a valuable parameter for evaluating the biological behavior of mucoepidermoid carcinomas of the salivary glands.

BACKGROUND:DNA ploidy pattern is sometimes used as a prognostic factor. Heterogeneity of a tumor could, however, give false information when a single analysis is performed. METHODS:Twenty-eight patients with adenoid cystic carcinomas were retrospectively studied with regard to clinico-histologic parameters, and in 24 of these the DNA pattern was assessed using flow cytometry, with multiple analysis from different tumor parts, to determine prognostic factors. RESULTS:Of the carcinomas, 33% (8/24) were DNA aneuploid, and 17% (4/24) of the tumors showed intratumoral heterogeneity of DNA content; two of them with mixture of diploid and aneuploid stemlines. The DNA aneuploid tumors were clinically more advanced and demonstrated a higher frequency of solid architecture than did diploid tumors (p < 0.05). The S-phase values were significantly higher in aneuploid samples than in diploid ones (p < 0.05). The recurrence rate was significantly higher in patients with aneuploid tumors (75%) than with diploid ones (19%) (p < 0.05). The cumulative survival was worse for patients with aneuploid tumors than for those with diploid ones (p < 0.05). CONCLUSIONS:Our findings suggest a potentially important role for flow cytometry in evaluation of adenoid cystic carcinoma. It is of interest to observe that in some tumors both diploid and aneuploid stemlines can co-exist. If one sample is analyzed and demonstrates diploid cells, there is a 3% chance that the tumor is also heterogeneous with aneuploid stemlines. If one sample demonstrates aneuploid cells, there is a 7% chance for heterogeneity with diploid cells, as well. Two samples from different tumor parts can be considered representative.

Twelve cases of salivary duct carcinoma were examined clinically, pathologically and by flow cytometry to quantify their histological features as well as attempt to identify factors predictive of patient outcome. All of the tumours arose in the parotid gland. Eight of the twelve patients were male. Four patients died of disease (median survival 12.5 months); three are alive with disease; and five are alive with no evidence of disease (mean follow-up of 50 months). Two tumours arose in a pre-existing pleomorphic adenoma. Positive lymph nodes were present in eight of ten patients sampled; patients with two or more positive lymph nodes tended to die of their disease or be alive with metastases. Comedo necrosis, perineural invasion and vascular invasion were common findings by light microscopy. Ten of the twelve tumours were aneuploid. Neither clinical stage, tumour size, aneuploidy nor histological features correlated with patient outcome. This study confirms the aggressive nature of salivary duct carcinoma.

We have compared four different sialagogues and their degranulating effect on serous and mucous cells, and their long-term effects. From this and earlier experiments, even within the groups of α- and β-adrenergic agents used, the effects varied on the serous and mucous cells. Previous studies have shown that cyclocytidine effectively degranulates serous cells without signs of cellular damage, while carbachol predominantly affects mucous acinar cells but gives early rise to permanent gland damage. Noradrenaline affects both serous and mucous cells, predominantly affecting serous cells with initial mitochondrial damage. Clonidine partially depletes both serous and mucous cells of their granules, producing permanent cellular damage. One month after a single injection of cyclocytidine the early findings described had disappeared. Carbachol showed permanent damage to salivary gland parenchyma, and both noradrenaline and clonidine demonstrated a long-term effect on acinar mucinous cells.

Intratumor DNA heterogeneity was investigated by flow cytometric analysis of multiple samples taken from different sites of 8 benign and 16 malignant primarily resected salivary gland tumors. All benign tumors had diploid DNA content. The overall incidence of DNA diploidy in 16 malignant cases examined was 50%. Intratumor differences in DNA ploidy were observed in four malignant tumors (25%); 2 of these 4 heterogenous tumors contained both aneuploid and diploid cell clones. The remaining 12 tumors showed a homogeneous DNA content in the different specimens; 8 were diploid, 3 aneuploid, and 1 was polypoid. The DNA nondiploid tumors were clinically more advanced than the DNA diploid ones (p < 0.01). The tumor proliferation rate (fraction of cells in S-phase) was higher in DNA nondiploid samples than in diploid ones (p < 0.01). The DNA nondiploid tumors seemed to recur more often than DNA diploid ones did. The data emphasize the usefulness of DNA measurements for the characterization of malignant salivary gland tumors but also the importance of adequate sampling in assessing their DNA ploidy. (C) 1993 John Wiley & Sons, Inc.

The degranulation and regranulation process was investigated after alpha-adrenergic stimulation on the rat submandibular gland. The submandibular gland in rat contains both serous and mucous cells. It has earlier been shown that serous cells filled with heavy-metal granules, are markedly more radiosensitive than cells without granules. In experiments with emptying the serous cell of their content of granules by administering an alpha-adrenergic stimulant, cyclocytidine, there has been found a decrease in irradiation damage in salivary gland tissue after irradiation. Injection of cyclocytidine, 150 mg/kg, was given i.p. to the rat. After 1 h there was almost complete depletion of granules in the serous cells, no morphological aberration was seen in the mucous cells. This effect still remained after 6 h. A beginning of regranulation with apical granules was seen 12 h after injection. After 24 h an almost complete regranulation had occurred in the salivary gland serous cells. The mucous cells did not show any morphological aberration. Our intent is to reduce unwanted salivary gland damage in patients with head and neck cancer when treated with radiotherapy. Depletion of heavy-metal granules in serous cells, before irradiation may diminish morphological destruction in the salivary glands. As a nearly total degranulation is present between 1-6 h after stimulation, this should be the optimal time for radiotherapy.