PASD1 Expression in Malaysian Hematological Malignancies Patients

Abstract

Per ARNT SIM domain containing 1 (PASD1) protein belongs to the Cancer Testis Antigen (CTA) family. It shows restricted expression in normal tissues but are highly expressed in cancer tissues. This study aims to further investigate PASD1 expression in Malaysian hematological malignancies patients as a potential biomarker for disease progression and vaccine development. Formalin-fixed Paraffin-Embedded (FFPE) tissue specimens from hematological malignancies patients were labeled with anti-PASD1-1 and anti-PASD1-2 antibodies using immunohistochemistry method. Our results show that among DLBCL patients, 7 samples were positive for PASD1-1, 2 samples were positive for PASD1-2 while 3 samples were positive for both of the antibodies. In addition, only 1 sample from T-cell Lymphoblastic Lymphoma (TLL) showed positive staining with PASD1-1. Other classes of hematological malignancies did not show any positive staining with either antibody. Antibody PASD1-1 stained the membrane and cytoplasm of the tumor cells strongly. Moderate nuclear labeling was also observed in some cases of DLBCL with PASD1-2. PASD1-1 staining was more frequent compared to PASD1-2 in most of the samples. Positive PASD1 staining was observed in patients with age range between 36-71 years old, higher in male cases than female by 54% and higher in Malay patients compared to Chinese by 77%. Due to its frequency, the PASD1_v1 protein may play a role in the DLBCL initiation and progression. A higher number of PASD1 staining in DLBCL samples compared to other lymphoma subtypes may suggest that PASD1 may represent a potential for DLBCL subtyping marker.

Cancer testis antigen PASD1 expression and immunogenicity in human colorectal cancer and polyps

“…We demonstrated a higher expression of PASD1-1 and PASD1-2 common region compared to the unique PASD1-2 protein. Similar findings were also observed in the PASD1 expression study in lymphoma particularly the DLBCL patients ( Cooper et al, 2006 ; Johdi et al, 2019 ). This might due to the longer epitope coverage in the PASD1-1 and PASD1-2 common region which started from 195 to 474 aa while the unique region only covered from 540 to 773 aa ( Cooper et al, 2006 ).…”

“…As expected with normal tissues, no PASD1 expression was observed in the human normal tonsil tissue (negative control for PASD1 expression, indicating the high specificity of the PASD1 antibodies in detecting the PASD1 protein expression. This study is also following previously published data on PASD1 protein expression and localization in the tissues ( Cooper et al, 2006 ; Johdi et al, 2019 ). These findings show that PASD1 is indeed an ideal candidate for an immunotherapeutic target due to its expression specificity.…”