[Genetic research with stored human tissue: a coding procedure with optimal use of information and protection of privacy]. / Genetisch onderzoek met opgeslagen lichaamsmateriaal: een coderingsprocedure met optimaal gebruik van informatie bij behoud van privacy.

To answer research questions concerning the course of disease and the optimal treatment of hereditary breast cancer, genetic typing together with the clinical and tumour characteristics of breast cancer patients are an important source of information. Part of the incidence of breast cancer can be explained by BRCA1 and BRCA2 germline mutations, which with current techniques can be retrospectively analysed in stored, paraffin-embedded tissue samples. In view of the implications of BRCA1- or BRCA2-carrier status for patients and other family members and the lack of clear legal regulations regarding the procedures to be followed when analysis is performed on historical material and no individual informed consent can be asked from the patients, an appropriate procedure for coding such data or rendering it anonymous is of great importance. By using the coding procedure described in this article, it becomes possible to follow and to work out in greater detail the guidelines of the code for 'Proper secondary use of human tissue' of the Federation of Biomedical Scientific Societies and to use these valuable databases again in the future.

Oral platinum analogue JM216, a radiosensitizer in oxic murine cells.

This study was designed to compare radiosensitization by the oral platinum compound JM216 with cisplatin. RIF1 mouse tumour cells were treated at various doses and at various exposure times with JM216 and irradiated 15 min before the end of drug exposure. The fraction of cells surviving treatment was assessed by colony formation. Results were compared with those for equivalent treatments with cisplatin. JM216 alone showed exponential killing of RIF1 cells, being approximately three times less efficient than cisplatin on a molar basis. For radiosensitization studies, drug doses used gave approximately 50 or 90% cell killing alone. No radiosensitization was seen after 2-h drug exposures, but significant radiosensitization occurred after 1- and 0.5-h exposures (shorter times required proportionally higher drug doses, giving equivalent drug kill). The enhancement ratio and time dependence were similar for the two platinum compounds, reaching 1.5 at the highest concentrations tested. Drug DNA adduct formation was assessed using immunocytochemistry with the NKI-A59 antiserum raised to cisplatin-DNA adducts. The antiserum was shown to recognize JM216-DNA adducts in a dose-dependent manner and maximum nuclear staining was found to be correlated with cell kill for both drugs. However, neither the level of staining at the time of irradiation nor at the time of maximum adducts correlated with radiosensitization, indicating that the number of DNA adducts did not determine radiosensitization. Intracellular glutathione levels were shown to be decreased by the drug, but only by approximately 50%, implying that this was not the cause of the increased radiosensitivity. In summary, JM216 was shown capable of radiosensitizing a platinum-sensitive tumour line to an extent similar to cisplatin. Radiosensitization was exposure-time and drug-concentration dependent, but was not dependent on DNA adduct levels nor glutathione depletion. In contrast, cell kill after drug alone was well correlated with adduct levels. These data suggest that JM216 could replace cisplatin in combined radiotherapy-chemotherapy studies, and also indicate that the NKI-A59 antibody could be used to monitor exposure levels in vivo.