Summary Prognostic information is essential for the evaluation, judgement and optimal treatment of patients with squamous cell cancers (SCCs)

The aetiology of branchial cysts is unknown. It is possible that they arise by more than one mechanism. The major theories are that they originate either from the branchial apparatus or from lymphoid tissues. A retrospective review was conducted of 61 cases occurring over a recent 14-year period. Eighty-five percent were diagnosed after the age of 10 years, 80% occurred in the 'classical' position, 80% had a squamous epithelial lining and 87% had lymphoid tissue in the wall. The clinical and histological features strongly support the lymphoid aetiology theory for the majority of branchial cysts.

Summary We report the use of tumour antigen (TA-4) polyclonal antiserum to assess the level and pattern of TA-4 antigen expression in formalin-fixed paraffin-embedded tissue sections from 110 patients with a range of normal, dysplastic and malignant squamous epithelia from various sites in the upper aerodigestive tract. There was a high degree of TA-4 antigen expression in the superficial layers of normal squamous epithelium and in well-differentiated squamous cell cancers (SCC). TA-4 expression was consistently absent in dysplastic oral squamous epithelium and in poorly differentiated SCCs. The degree of cellular heterogeneity in moderately differentiated SCCs was such that morphologically identical squamous cancer cells could be distinguished on the basis of TA-4 expression. Immuno-electron microscopy localised Tumour-associated antigen (TA-4) is a glycoprotein of molecular weight 48 kDa originally extracted and subsequently purified by Kato and Torigoe (1977) from a patient with squamous cell cancer (SCC) of the uterine cervix. Subsequent studies using immuno-histochemistry and a radioimmunoassay technique have reported that the expression of TA-4 antigen in cervical squamous carcinoma is related to tumour cell differentiation (Maruo et al., 1985) and that serial serum levels of antigen are valuable in monitoring a patient's progress following completion of definitive treatment (Maruo et al., 1985;Kato et al., 1979).The only other study dealing with tissue localisation of TA-4 antigen reported the invariable presence of TA-4 in normal differentiated cervical squamous cells and in differentiated SCCs (Maruo et al., 1985). Our present study was undertaken in an attempt to further define the cellular localisation and cellular specificity of this antigen, and to determine whether previous results in relation to cervical cancer are also applicable to SCCs of the head and neck (oral cavity, larynx, pharynx) region. Materials and methodsTissue specimens Specimens were obtained from 110 patients with either leukoplakia or invasive squamous cell cancers, of various sites in the head and neck region (oral cavity 72, larynx 18, pharynx 10). These consisted of 85 males and 25 females, with a mean age of 62.5 years (range 28-82 years). Each specimen had been formalin-fixed and paraffin-embedded within 60 min of removal. Serial 4 ,im thick sections were cut from each block, and one slide was stained with haematoxylin and eosin for routine histopathological examination. Histological grading was performed by R.C. There was a range of patterns within each tumour. When there was predominantly keratinisation with squamous epithelial pearls, the tumour was graded as well differentiated. When keratinisation was present only in some areas of the tumour, it was graded as poorly differentiated. When there appeared to be a fairly even mixture of keratinising areas and non-keratinising areas, the tumour was graded as moderately well differentiated. Some keratinisation was present in all of the tumours studied. ImmunohistochemistryFo...