Increased numbers of alveolar macrophages with apoptotic bodies predict lung carcinoma

In our previous study on fixed tissue blocks, we reported a high apoptotic rate in patients with operated small cell lung carcinomas. In addition to tumour cells, numerous apoptotic bodies could also be found within alveolar macrophages within and close to tumour tissue. In order to test if such cells could be found in sputum smears and if their presence could be utilized as a marker in tumour diagnosis, we analyzed the occurrence of alveolar macrophages with apoptotic bodies (AMWABs) in a set of sputum smear and BAL samples from patients with and without a pulmonary malignancy. An increased amount of AMWABs in the cytoplasm could be found in sputum and BAL samples from patients with lung cancer. Interestingly, AMWABs could also be seen in patients with a histologically confirmed pulmonary malignancy, but with no detectable tumour cells in their sputum smear. Thus, the presence AMWABs in sputum smears could serve as a more sensitive marker of pulmonary malignancy than the presence of malignant cells per se. This is the first report describing apoptotic bodies in macrophages and the utility of their detection in cancer diagnosis.