BCL2L1 and retinoblastoma: Studies analyzing Bcl-XL expression patterns have also demonstrated the up-regulation of this protein in invasive and metastatic cancer cell populations and the correlation of Bcl-XL expression with the invasion (vascular or stromal invasion) and metastasis (lymph node or distal metastasis) of retinoblastoma [37], breast cancer [10, 38], colon cancer [39], tongue cancer [40], and hepatocellular carcinoma cells [41].