JAK2 and small cell lung carcinoma: However, in the more complex environment of stromal interaction, JAK2 blockage alone was not able to inhibit the SCLC cell adhesion to the stroma, whereas CXCR4 inhibition by TN14003 was fully efficient (Figure 4), demonstrating activation of branched pathways triggered by CXCL12 binding to CXCR4.