Summary.-Ten cell lines of human squamous carcinomas of the tongue and larynx have been established from surgical specimens removed from 36 unselected patients, in order to provide systems for investigating the invasive and tissue-destructive capacity of squamous carcinomas of the head and neck. The morphology, ultrastructure and growth characteristics of the 10 lines are described. Detailed cytogenetic analysis of the first 4 lines indicates that each is karyotypically unique, with no evidence of cross-contamination. Nine of the 10 cell lines secrete immunoreactive / human chorionic gonadotrophin (/-hCG) in the culture medium. No correlation was demonstrated between the ability of the cell lines to secrete plasminogen activator and their capacity to grow in soft agar or as xenografts in immune-deficient mice.

Summary.-Walker carcinosarcoma cells cause in vitro osteolysis which may be inhibited by aspirin. In the rat, this tumour produces osteolytic bone deposits and hypercalcaemia, both of which can be prevented by aspirin and indomethacin, whereas soft tissue tumour deposits are unaffected by these drugs. Some human breast tumours cause in vitro osteolysis which may be inhibited by aspirin.PATIENTS with breast cancer frequently develop abnormalities in their calcium metabolism, which are usually associated with osteolytic bone metastases (Galasko and Burn, 1971) and are caused by excessive mobilization of calcium from the skeleton. This raises the possibility that the mechanism for this skeletal calcium mobilization, and the ability of tumour deposits to develop into destructive bone deposits, may both depend on the ability of tumour cells to produce osteolytic substances.To investigate this hypothesis, we have used an in vitro organ culture system of neonatal mouse bone which releases calcium in response to known osteolytic substances. We have found that some, but not all, human breast carcinomata when added to the organ culture caused increased calcium release from the bones and that this osteolysis could be inhibited by aspirin.To test whether these in vitro observations were relevant to the in vivo behaviour of tumours, it was necessary to develop a suitable animal tumour model. For this, we chose the intra-aortic injection of Walker carcinosarcoma cells into the rat, because this tumour has been reported to cause hypercalcaemia (Raue et al., 1972) These were cultured for a further 3 days under the same conditions as for the preliminary period, during which time calcium passed from the bone into the medium. At the end of the culture period the 45Ca in the medium, and remaining in the bone, was estimated using a Packard scintillation counter. The

No abstract