PMS2 antibody is a specialized immunological tool targeting the PMS2 protein, a critical component of the DNA mismatch repair (MMR) system. PMS2 (Postmeiotic Segregation Increased 2) forms a heterodimer with MLH1 to constitute the MutLα complex, which corrects DNA replication errors and maintains genomic stability . Antibodies against PMS2 are primarily used in immunohistochemistry (IHC) and molecular research to assess MMR deficiency, which is linked to hereditary cancers (e.g., Lynch syndrome) and microsatellite instability (MSI) in tumors .
PMS2 repairs mismatched bases during DNA replication and recombination. Loss of PMS2 expression disrupts MMR, leading to MSI and increased cancer risk .
Germline PMS2 mutations are associated with Lynch syndrome and Turcot syndrome, particularly when biallelic mutations occur .
PMS2 IHC staining is a gold standard for identifying MMR-deficient tumors. Loss of nuclear PMS2 expression in tumor cells (retained in stromal cells) suggests MMR deficiency .
Combined with MSH6 staining, PMS2 antibodies form a two-antibody algorithm for efficient MMR testing, achieving a 99% detection rate of MMR deficiency in colorectal cancer .
| Antibody Clone | Application | Observed Band Size (Western Blot) | Specificity Confirmed By |
|---|---|---|---|
| EPR3947 (ab214442) | IHC, WB, Flow Cyt | 120 kDa (vs. predicted 96 kDa) | Knockout cell lines (HeLa, HAP1) |
| C-20 (Source 2) | Western Blot | 96 kDa | Protein truncation in mutants |
Western Blot: PMS2 antibodies detect a ~120 kDa band in wild-type cells, absent in PMS2 knockout controls .
Immunohistochemistry: Robust nuclear staining in normal tissues (e.g., colon, breast), with loss observed in MMR-deficient tumors .
| Tumor Stage | PMS2 mRNA Level (Mean ± SD) | PMS2 Protein Expression (%) | Remmele Score |
|---|---|---|---|
| Normal | 1.00 ± 0.00 | 95–100% | 9.0 |
| Stage I | 0.92 ± 0.18 | 51–100% | 7.5 |
| Stage IV | 0.47 ± 0.23 | <1% | 3.0 |
PMS2 mRNA and protein levels decrease significantly with tumor progression (P < 0.001) .
Loss of PMS2 correlates with poor differentiation and advanced staging .
Prostate Cancer: Restoring PMS2 expression in PCa cells suppresses tumor growth (in vitro and in vivo) by inducing apoptosis and downregulating anti-apoptotic BCL2A1 .
Knockout Mice: Pms2⁻/⁻ mice exhibit elevated mutation rates, lymphomas, and impaired antibody class-switch recombination, highlighting PMS2’s role in genome integrity .
Pseudogenes: PMS2 shares homology with >13 pseudogenes (e.g., PMS2CL), complicating PCR and sequencing analyses .
Antibody Cross-Reactivity: Some clones may detect nonspecific bands; validation using knockout controls is essential .