DNA ploidy has been determined by flow cytometry in 28 surgical specimens from patients with adenocarcinoma of the lung (tumor diameter, 3.0 cm or less), and the relationship between DNA ploidy and the clinical stage and survival also has been investigated. The cases were classified according to the DNA index (DI) into group A (DI 1.00 to 1.50), group B (DI 1.51 to 2.00) and group C (DI greater than 2.01). A close relationship was observed between the DI and the survival rates but not between the DI and the clinical stage. Tumor ploidy is considered to be one of the prognostic factors and may be useful in selecting adjuvant therapy.

Clinical trials of natural interferon-alpha (HLBI) in the treatment of Philadelphia chromosome (Ph1) positive chronic myelogenous leukemia (CML) were carried out in a cooperative study of 22 institutions in Japan. Patients with CML in chronic and accelerated phase were given intramuscular or subcutaneous injections of HLBI at the dose of 6 X 10(6) U/body on consecutive days. Of the 47 patients in this study, forty-one were evaluable for clinical effects, and 42 could be assessed for adverse effects. Among 30 evaluable patients in the chronic phase, 9 (30.0%) achieved complete remission (CR) and 20 (66.7%) partial remission (PR). Only one patient had no response (NR), and the response rate (CR + PR) in chronic phase was 96.7% (29/30). Among 11 patients in the accelerated phase, 3 (27.3%) achieved CR and 4 (36.4%) PR. The response rate in the accelerated phase was 63.6% (7/11). In all 41 evaluable patients, the response rate was 87.8% (36/41). In 5 of 13 responding patients treated for more than 6 months, cytogenetic investigation showed the decline of Ph1 positive bone marrow cells from 100% to 92-0% (mean 46%). Adverse effects such as fever (52.4%), general fatigue (35.7%), and liver dysfunction (21.4%), were observed, but they were usually mild and reversible. No patient was taken off this study because of these toxicities. The results confirm the clinical efficacy of HLBI in patients with CML in the chronic and accelerated phase.

Recent recombinant DNA techniques have made possible the production of gene probes and the search for genetic damage in neoplastic cells, and now occupy one of the central place in cancer research. More recently, detection of immunoglobulin and T cell receptor gene rearrangements has been shown to be a powerful procedure for identifying monoclonality and the cellular lineage of lymphoid cells even when conventional studies give an ambiguous diagnosis. Such genetic markers are not only useful for differential diagnosis and classification, but serves also as a sensitive unique clonal marker to detect early cancer relapse. In a similar manner, chromosomal translocations associated with specific disease types can be detected with DNA probes in southern blot analysis without the use of conventional cytogenetics. These methods have wider application and will play an increasing role in the clinical use in the near future.

Two mutant cell lines, R-1 and R-2, have been isolated from EJ/NIH (NIH/3T3 transformed by a human activated c-Ha-ras gene) by treatment with ethyl-methane-sulfonate (EMS). They reveal various characteristics of normal cells, and seem to have reversed to the original cells. Especially, R-1 shows a very flat morphology, complete contact inhibition, anchorage dependent cell growth and no tumorigenecity. Although transformed phenotypes are intensively suppressed, R-1 does not seem to secrete suppressive factors to the parent cell line. The activated c-Ha-ras (EJ-ras) could be detected as a 6.6 kb BamHI fragment in R-1 as well as in EJ/NIH. The level of transcription and translation in R-1 was also the same as that in EJ/NIH. Moreover, the DNA isolated from R-1 cells had a high transforming activity to NIH/3H3, suggesting that R-1 contained the EJ-ras as an activated oncogene. The levels of transcription of c-myc, c-fos, p53 and other ras family genes was unchanged between EJ/NIH and R-1. Further, R-1 cells are resistant to retransformation by EJ-ras, v-src, v-mos and SV40T genes, and DNAs isolated from EJ/NIH or NIH/3T3 could not transform R-1 cells. All these findings suggest that some genes necessary for transformation by EJ-ras, except for c-myc, c-fos, p53 and ras proto-oncogenes, are defective or some inhibitory genes against transformation are enhanced in R-1 cells.