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Biochemical specifity of malignant melanoma is represented in part by the formation of specific cytoplasmatic particles of the pigment cell--melanosomes--in which the synthesis of pigment eumelanin and pheomelanin takes place and in part by the presence of a specific enzyme--tyrosinase--which catalyzes the formation of pigment eumelanin and pheomelanin and even the formation of specific metabolites (so called melanogens) which are excreted in increased amounts in the course of the disease. Tyrosinase and melanogens are specific for pigment cell and therefore can be used for monitoring of melanogenesis in malignant melanoma. When comparing our results and the results of other authors we can conclude that following of specific markers of melanogenesis in malignant melanoma should serve for the evaluation of prognosis of the disease. The study of melanoma markers is by far not finished. We do hope that nearly future will be able to give a sufficient answer to the question, whether melanogenuria is actually an expression of expected different biochemical or metabolic types of malignant melanoma on the one hand and/or biochemically or immunologically conditioned responses of the host organism on the other.

Two tyrosinase isozymes were purified from pigmented hamster melanoma and injected i.v. into rats. It was shown that while T1 (sialylated) isozyme survived in the circulation, native asialo (T2) isozyme and neuraminidase-desialylated T1 isozyme disappeared from the circulation in a few minutes. Desialylated fetuin had a marked inhibitory effect on the removal of asialo-T1 tyrosinase. These data indicate that the enzyme tyrosinase shares the common pattern of clearance from circulation known for the majority of serum glycoproteins. The electrophoretic pattern of tyrosinase isozymes partially purified from the sera of melanoma-bearing animals were compared with those from the soluble fraction of the tumors. In hamsters, melanoma tissue revealed both T1 and T2 isozymes while serum exhibited T1 and very weak T2, supporting the mechanism of clearance demonstrated in rats. In mice bearing Cloudman S-91 or B-16 melanomas, only T1 isozyme was seen in sera and in tumors.

The clinical results from postoperative active specific immunotherapy using autologous polymerized tumor material in six patients suffering from metastasized melanoma is reported. Correction of an alleged systemic deficiency leading to malignant cell transformation was attempted by administering certain essential trace elements, amino acids, vitamins, and a diet containing lipids, extracted from the mammalian central nervous system, after heating. Vaccinations against influenza were also given as a precaution against certain viral infections sometimes seen to precede melanoma recurrence. The clinical results with this postoperative adjuvant therapy are so encouraging that we suggest that sterile tumor tissue should be saved at operation and treated to produce insoluble particles as an option for postoperative treatment of patients suffering from metastasized melanoma. Prospective randomized studies are indicated.

The excretion of Thormählen positive melanogens (TPM), zincuria, serum dopaoxidase activity of tyrosinase and serum sialic acid were determined in 60 patients with primary and/or metastatic cutaneous melanoma and in 20 healthy persons. On the basis of our results we can recommend the following of TPM urinary excretion and serum dopaoxidase activity in the course of malignant melanoma as specific markers of the tumor growth. The following of serum sialic acid in the course of malignant melanoma is valuable from the standpoint of prognosis of the disease. The following of zincuria in the course of malignant melanoma is not recommended because of its low value for monitoring melanoma patients.

A simple screening test for estimation of some phenolic and indolic compounds in urine is described. The method is rapid, simple and able to detect all the indolic and phenolic compounds observed, including o-dihydroxy compounds. The method is based on the color reaction with reagent solution composed of sodium tungstate, trichloroacetic acid, hydrochloric acid and sodium nitrite. After alkalinization by sodium hydroxide the optical density is measured at 405 and 490 nm. The latter is specific for o-dihydroxy compounds. This test seems to be useful for estimation of phenolic and indolic compounds in urine of patients with increased production of compounds of this nature, particularly in some tumors.