A differential diagnosis of LCa can be based on cytology or tumour markers such as carcinoembryonic antigen and CYFRA21-1; for tuberculosis pleurisy among IF, it can be based on adenosine deaminase; and for inflammatory pleurisy, a differential diagnosis can be achieved based on neutrophilia in pleural fluid. This evidence concerns the gene CEACAM5 and Leber congenital amaurosis.