Furthermore, among the 7 other matched lung cancer tissue types (2 carcinoid, 1 carcinoma, 1 small cell, 1 small and large cell, 1 nonsmall cell, and 1 bronchoalveolar) mean Id1 expression was significantly lower in tumor as compared to matched normal tissue (P = .007) (Figure 3(c)). Here, ID1 is linked to carcinoma.