SFTPA2 and adenocarcinoma: Different SP-A levels are found in lung diseases as exemplified by higher SP-A1/SP-A2 levels in patients suffering from adenocarcinoma which correlates with tumour-grading [28], higher level in patients with alveolar proteinosis [29] or reduced levels in diseases such as the Acute Respiratory Distress Syndrome (ARDS) [30].