“…Infections may be one of the most common causes of lung cancer progression, associated with decreased patient response to treatment, poorer prognosis, and increased mortality [ 10 , 11 ]. One of the newer research areas observed in recent years is the discussion of the role and involvement of Streptococcus pneumoniae (not only in the progression of lung cancer but also in its participation in the process of carcinogenesis itself) [ 12 , 13 , 14 , 15 ]. This is related to the increased susceptibility to infections caused by these Gram-positive bacteria, which can cause invasive and non-invasive pneumococcal disease, observed among cancer patients.…”