The IgG1/G2 subclass shift - a sensitive, tissue nonspecific marker for malignancy. Diagnostic performance with squamous cell carcinoma of the head and neck

A significant decrease in %IgG1 accompanied by an increase in %IgG2 in tota l serum IgG has been previously reported as a highly sensitive marker for d etecting early stages of carcinomas of various localizations. Here we inves tigated the question as to whether this phenomenon is also observed in sera of patients with squamous cell carcinoma of the head-neck region (SCC-HN), and to evaluate its diagnostic performance in the post-operative monitorin g. Using quantitative affinity chromatography, serum concentrations of IgG1 , IgG2 and total IgG were determined in 81 patients with different stages o f primary and untreated SCC-HN, in 51 SGG-HN patients in post-therapeutical follow up, and in 33 patients with organ matched benign diseases. The data were compared with a total of 174 healthy controls. It was found that (i) 105 SCC-HN patients exhibited a mean value of 56.0 +/- 0.7% IgG1, which lik ewise differed from healthy controls (63.2 +/- 0.5) and benign diseases (61 .5 +/- 1.0) with P < 0.0005, (ii) sensitivities and specificities for discr iminating primary malignancies from healthy controls were 70 and 74% respec tively, and from benign diseases 65 and 76%, (iii) highest sensitivities an d specificities were observed with posttherapeutic cases suffering from tum our recurrence (88% and 75%) or patients with distant metastases (87% and 8 6%), (iv) apparently tumour-free post-therapeutic patients showed a mean %I gG1 not different from the normal value. The decrease in %IgG1 accompanied by increased %IgG2 is an efficient, sensitive and early marker of SCC-HN, w hich appears particularly useful for the post-therapeutic monitoring.