In several countries, increased incidence of squamous cell carcinoma (SCC) of the tongue in young adults has been suspected during the last decades. Some reports indicate a lower survival rate for young patients compared to older patients. In other reports, there has not been any considerable difference in survival when comparing young adults to older patients, whereas some authors have shown better survival for young adults. This disease is rare in young adults, and early reports were based on comparable small numbers and selected patients. Our aim was first to perform a population-based study to determine if an increased incidence in SCC of the tongue could be verified in a larger population comprising the Scandinavian countries Denmark, Finland, Sweden and Norway. A second aim was to determine survival rates for young adults compared to older patients. The material was based on the annual cancer incidence and survival reports from the Scandinavian cancer registries. The study period was 1960 -1994. During that period, 5,024 SCCs of the tongue were reported. Of these, 276 (5.5%) were young adults (20 -39 years). The incidence increased at all ages except for women 65-79 years old. The increase was most pronounced in young adults: 0.06 -0.32 for men and 0.03-0.19 for women, counted by 100,000 person-years. Relative survival was significantly better for young adults compared to older patients.

The incidence of and mortality from squamous cell carcinoma (SCC) of the tongue have increased during the recent decades in the Western world. Much effort has been made to predict tumour behaviour, but we still lack specific prognostic indicators. The aim of our study was to evaluate the relative importance of the known demographic, clinical and histological factors in a homogeneous population-based group of patients with SCC of the mobile tongue. The demographic and clinical factors were reviewed retrospectively from primary and tertiary care patient files. Histological prognostic factors were determined from pre-treatment biopsies. The TNM stage was found to be the most important prognostic factor. In particular, local spread outside the tongue rather than spread to regional lymph nodes was related to poor prognosis. Several demographic and histopathological factors were closely related to TNM stage. When the cases were divided into stage I–II carcinomas and stage III–IV carcinomas, it appeared that the patient’s older age (> 65 years), a high malignancy score and an absence of overexpressed p53 protein were associated with a poorer prognosis in stage I–II carcinomas. Such cases may require more aggressive treatment. Among patients with stage III–IV carcinomas, heavy use of alcohol was significantly associated with a poor disease-specific survival time. © 2000 Cancer Research Campaign

Squamous cell carcinoma (SCC) of the tongue is the most common cancer in the oral cavity and has a high mortality rate. A total of 90 mobile tongue SCC samples were analysed for Bryne's malignancy scores, microvascular density, and thickness of the SCC sections. In addition, the staining pattern of cyclooxygenase-2, avb6 integrin, the laminin-5 g2-chain, and matrix metalloproteinases (MMPs) -2, -7, -8, -9, -20, and -28 were analysed. The expression of MMP-8 (collagenase-2) was positively associated with improved survival of the patients and the tendency was particularly prominent in females. No sufficient evidence for a correlation with the clinical outcome was found for any other immunohistological marker. To test the protective role of MMP-8 in tongue carcinogenesis, MMP-8 knockout mice were used. MMP-8 deficient female mice developed tongue SCCs at a significantly higher incidence than wildtype mice exposed to carcinogen 4-Nitroquinoline-N-oxide. Consistently, oestrogen-induced MMP-8 expression in cultured HSC-3 tongue carcinoma cells, and MMP-8 cleaved oestrogen receptor (ER) a and b. According to these data, we propose that, contrary to the role of most proteases produced by human carcinomas, MMP-8 has a protective, probably oestrogen-related role in the growth of mobile tongue SCCs.

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