SHIFT IN IGG-SUBCLASSES - A RELIABLE, TISSUE NONSPECIFIC MARKER FOR SQUAMOUS-CELL CARCINOMA OF THE HEAD AND NECK

Aim: Until now no serological markers were available towards the diagn osis of squamous-cell carcinomas of the head and neck (HNSCC) particul arly in the detection of posttherapeutic recurrent diseases and metast ases. Previous reports described patients with malignant diseases of v arious tissues exhibiting a characteristic and highly significant alte ration in the subclass composition of serum IgG;, consisting of a redu ction in %IgG1 and an increase of %IgG2. In this study we present for the first time results of this IgG-shift in patients suffering from HN SCC. Patients and Methods: A total of 111 patients was investigated at our clinic, all suffering from primary, histopathologically verified squamous cell carcinomas of the head and neck. These patients were inv estigated as to %IgG1/IgG2 prior to any treatment. A second group cons isted of 35 patients with local recurrences, 15 patients with distant metastases and 27 patients without tumour at the time of investigation , who were in observation for 1 to 5 years after primary treatment (TO ). Thirdly, a total of 33 patients was included who were afflicted wit h a variety of benign diseases of the head and neck, such as chronic r hinosinusitis, chronic tonsillitis and also lateral or median cysts of the neck. Data of the three groups were compared with those of 174 he althy volunteer controls. 5 mi blood were taken from a forearm vein an d the quantitation of subclasses IgG1, IgG2 and total Ige was performe d by affinity chromatography. The single values obtained with all expe rimental groups and healthy controls showed normal distribution for pr imary cancer patients versus healthy control. Accordingly, significant differences between mean values were calculated with the two-sided St udents t-test, and cut-off values were calculated as the arithmetic me ans of mean values obtained from the groups to be compared. Diagnostic sensitivities and specificities were defined as percentages of patien ts with %IgG1 smaller, and of healthy controls with %IgG1 greater than the cut-off value. Results: We found a highly significant alteration in the subclass composition of serum IgG, consisting of a reduction in %IgG1 and an increase in %IgG2 in our HNSCC groups. The present data suggest the changes in %IgG1 and %IgG2 as a useful serological tumour marker to detect primary or recurrent and/or metastatic squamous-cell carcinomas of the head and neck. Conclusion: The shift in %IgG1/%IgG2 exhibited diagnostic sensitivities and specificities comparable to, or - particulary at early tumour stages - by far higher than conventiona l serological tumour markers. Whereas conventional serological markers directly correspond to tumourogenically derived products, the shift i n %IgG1/IgG2 represents an indirect marker, consisting of a change of the host's immune system due to the presence of malignant tumours.