The capability of activated oncogenes to induce malignant transformation of immortalized cells in vitro has suggested that they have a similar role in the pathogenesis of human tumors. We previously found that activation of the K-ras oncogene by a point mutation in codon 12 occurs in about one third of human lung adenocarcinomas. We studied the clinical importance of this oncogene-activation in 69 patients with lung adenocarcinoma in whom complete resection of the tumor was possible. The polymerase chain reaction was used to amplify ras-specific sequences of DNA isolated from frozen or paraffin-embedded tumor samples. Ras point mutations were subsequently detected and classified with the use of mutation-specific oligonucleotide probes. Nineteen of the tumors harbored a point mutation in codon 12 of the K-ras oncogene. There was no association between the K-ras point mutation and the age at diagnosis, sex, or presence of previous or concurrent neoplasms. Tumors positive for K-ras point mutations tended to be smaller and less differentiated than those without mutations. The K-ras codon-12 point mutation was a strong (and unfavorable) prognostic factor: 12 of the 19 patients with K-ras point-mutation—positive tumors died during the follow-up period, as compared with 16 of the 50 patients with no mutation in the K-ras oncogene (P = 0.002). This difference in prognosis was also reflected in the duration of disease-free survival (P = 0.038) and in the number of deaths due to cancer (P<0.001). The presence of K-ras point mutations defines a subgroup of patients with lung adenocarcinoma in whom the prognosis is very poor and disease-free survival is not usually long despite radical resection and a small tumor load. (N Engl J Med 1990; 323:561–5.)

Background Induction chemotherapy before surgical resection increases survival compared with surgical resection alone in patients with stage IIIA-N2 non–small-cell lung cancer (NSCLC). We hypothesized that, following a response to induction chemotherapy, surgical resection would be superior to thoracic radiotherapy as locoregional therapy. Methods Selected patients with histologic or cytologic proven stage IIIA-N2 NSCLC were given three cycles of platinum-based induction chemotherapy. Responding patients were subsequently randomly assigned to surgical resection or radiotherapy. Survival curves were estimated using Kaplan–Meier analyses from time of randomization. Results Induction chemotherapy resulted in a response rate of 61% (95% confidence interval [CI] = 57% to 65%) among the 579 eligible patients. A total of 167 patients were allocated to resection and 165 to radiotherapy. Of the 154 (92%) patients who underwent surgery, 14% had an exploratory thoracotomy, 50% a radical resection, 42% a pathologic downstaging, and 5% a pathologic complete response; 4% died after surgery. Postoperative radiotherapy was administered to 62 (40%) of patients in the surgery arm. Among the 154 (93%) irradiated patients, overall compliance to the radiotherapy prescription was 55%, and grade 3/4 acute and late esophageal and pulmonary toxic effects occurred in 4% and 7%; one patient died of radiation pneumonitis. Median and 5-year overall survival for patients randomly assigned to resection versus radiotherapy were 16.4 versus 17.5 months and 15.7% versus 14%, respectively (hazard ratio = 1.06, 95% CI = 0.84 to 1.35). Rates of progression-free survival were also similar in both groups. Conclusion In selected patients with pathologically proven stage IIIA-N2 NSCLC and a response to induction chemotherapy, surgical resection did not improve overall or progression-free survival compared with radiotherapy. In view of its low morbidity and mortality, radiotherapy should be considered the preferred locoregional treatment for these patients.

The presence of cell-free microRNAs (miRNAs) has been detected in a range of body fluids. The miRNA content of plasma/serum in particular has been proposed as a potential source of novel biomarkers for a number of diseases. Nevertheless, the quantification of miRNAs from plasma or serum is made difficult due to inefficient isolation and lack of consensus regarding the optimal reference miRNA. The effect of haemolysis on the quantification and normalisation of miRNAs in plasma has not been investigated in great detail. We found that levels of miR-16, a commonly used reference gene, showed little variation when measured in plasma samples from healthy volunteers or patients with malignant mesothelioma or coronary artery disease. Including samples with evidence of haemolysis led to variation in miR-16 levels and consequently decreased its ability to serve as a reference. The levels of miR-16 and miR-451, both present in significant levels in red blood cells, were proportional to the degree of haemolysis. Measurements of the level of these miRNAs in whole blood, plasma, red blood cells and peripheral blood mononuclear cells revealed that the miRNA content of red blood cells represents the major source of variation in miR-16 and miR-451 levels measured in plasma. Adding lysed red blood cells to non-haemolysed plasma allowed a cut-off level of free haemoglobin to be determined, below which miR-16 and miR-451 levels displayed little variation between individuals. In conclusion, increases in plasma miR-16 and miR-451 are caused by haemolysis. In the absence of haemolysis the levels of both miR-16 and miR-451 are sufficiently constant to serve as normalisers.

To define the role of cellular oncogenes in human cancers, we studied the prevalence of mutational activation of ras oncogenes in untreated non-small-cell lung cancer. Genomic DNA was extracted from 39 tumor specimens obtained by thoracotomy and was examined for activating point mutations in codons 12, 13, and 61 of the H-ras, K-ras, and N-ras genes. A novel, highly sensitive assay based on oligonucleotide hybridization following an in vitro amplification step was employed.