Testicular cancer: B5, a new tumour marker

Tumour markers which occur in blood or urine are of value in the management of cancer patients because they allow disease status to be monitored by non-invasive techniques at low cost. An antigen, 'B5', on erythrocytes has been shown to become enhanced when cancer develops, regardless of tumour type, and thus the B5 antigen may be utilised as a 'universal' tumour marker. A simple haemagglutination test gives reliable quantitative assessment of the B5 marker status. Here, serial measurements of B5 status in 63 patients presenting with testicular cancer confirms a preliminary finding that both teratoma and seminoma are marked by B5. Of 28 patients with seminoma, 2 had a raised BHCG, whilst 20 (71%) were B5-positive, including 13 of 20 patients with stage-1 disease. After successful treatment, the large majority of patients showed a significant downward shift in their B5 status. Control subjects differed in that their B5 status remained constant and was often also very weak.

Identification of synergistic combinations of spirogermanium with 5-fluorouracil or cisplatin using a range of human tumour cell lines in vitro

A series of continuous human tumour cell lines, derived from various tumour types, were used to establish whether the combination of spirogermanium (SP) with other 'standard' antitumour drugs proved superior to these as single agents in reducing cell survival in vitro. A non-cytotoxic concentration of SP was selected and when combined with a range of concentrations of cisplatin or 5-fluorouracil (5-FU), definite synergistic cell kill was noted in all lines tested. In contrast, the combination of SP with various other antitumor drugs, including adriamycin, methotrexate and the vinca alkaloids and with X-irradiation did not enhance cytotoxicity. These pre-clinical in vitro studies suggest that benefit may accrue from combining SP with either 5-FU or cisplatin and provide a basis for their clinical evaluation in colo-rectal tumours or transitional cell cancer of the bladder, respectively.

Cyclosporine does not prevent cytoplasmic calcium changes associated with lymphocyte activation

The recent development of fluorescent reagents that are sensitive to calcium ions has made it possible to quantitate cytoplasmic calcium levels of lymphocytes. The cytoplasmic calcium concentration more than doubles within the first few minutes following lymphocyte stimulation. Here I show that it is likely that this increase in calcium is an absolute requirement for mitogenic commitment. Brief exposure of T cells to concanavalin A (Con A) is sufficient to stimulate cell division, provided that extracellular calcium ions are available to the cells at the time of exposure to mitogen--no mitogenesis occurs if extracellular calcium is below 10(-5)M. Commitment to mitosis requires both Con A acting at the cell surface and a source of extracellular calcium, so it follows that the plasma membrane is implicated in the control of cytoplasmic calcium changes. The lipid-soluble nature of cyclosporine (Cys) results in the partitioning of this drug into the plasma membrane of lymphocytes; the possibility arises that Cys might inhibit lymphocyte activation by perturbing membrane structure so as to alter regulatory fluxes in cytoplasmic calcium. Experiments reported here show that early changes in cytoplasmic calcium levels of activated T cells occur normally in the presence of Cys.

A new indicator of human malignant tumour

In haemagglutination tests we have found that the monoclonal antibody B5 discriminates between erythrocytes from patients with malignant cancer (total 386; greater than 80% B5 positive) and individuals with no known tumour (total 247; less than 20% B5 positive). The B5 antigen detected on intact erythrocytes is a tightly bound surface component which does not appear to be derived from the plasma. The B5 antigen is not T, Tn, Ca1, CEA or the Forsmann antigen; nor is it related to any of the major blood group antigens. Abnormal levels of surface B5 are found on erythrocytes from patients with a great diversity of tumours and this fact presents B5 as an indirect marker of malignancy. Successful eradication of tumour is associated with a switch from positive to negative B5 haemagglutination. We believe that B5 is a valuable addition to the few useful tumour markers already employed for monitoring tumour status.

The effect of ascorbic acid (vitamin C) on two tumor cell lines in culture

The effect of vitamin C on cell proliferation and DNA synthesis was investigated using two tumor cell lines Hep2 and KB. The results show that there was an increase in the ratio of dead to live cells and a decrease in the rate of DNA synthesis. The results also agree with other work carried out on animal experimental models which claimed that vitamin C may be involved in the arrest of neoplastic cell proliferation.