Purpose: Placenta-specific protein 1 (PLAC1) is one of the members of cancer-testis antigens family that has limited expression in normal tissue, but is upregulated in a variety of malignant tissues. Considering the lack of studies on the expression of FCRL1 in CML and CLL, the current study was conducted to examine the expression pattern of PLAC1 gene in these leukemias. 
Materials and Methods: Fresh peripheral blood samples were collected from 6 CML and 10 CLL patients. In addition, peripheral blood samples of 10 healthy individuals were collected in EDTA as control group. All patients and healthy individuals signed a consent letter before sampling. The mononuclear cells were separated using ficoll-hypaque gradient centrifugation. Isolated mononuclear cells were used for RNA extraction and cDNA synthesis using RT-PCR method. Then, PLAC1 transcript expression in comparison to GAPDH were detected via Real-Time PCR. The statistical analyses were performed using chi-square test in SPSS.
Results: All 10 normal samples were negative for PLAC1. The PLAC1 expression was found to be statistically different in CML group (4 out of 6 cases) compared with that in the normal group (Pvalue = 0.000). However, CLL revealed no significant difference compared to normal individuals for PLAC1 expression (P Value = 0.648). In a significant percentage of CML patients, PLAC1 expression was positive but in CLL patients PLAC1, transcript expression was not evident. 
Conclusion: It seems that PLAC1 could potentially be proposed as a biomarker in CML to aid in the diagnosis, prognosis, and treatment in the future.