Expression of coagulation factor XIII subunit A in acute promyelocytic leukemia

Genetic landscape in coagulation factor XIII associated defects – Advances in coagulation and beyond

Coagulation factor XIII (FXIII) acts as a fine fulcrum in blood plasma that maintains the balance between bleeding and thrombosis by covalently crosslinking the pre-formed fibrin clot into an insoluble one that is resistant to premature fibrinolysis. In plasma, FXIII circulates as a pro-transglutaminase complex composed of the dimeric catalytic FXIII-A encoded by the F13A1 gene and dimeric carrier/regulatory FXIII-B subunits encoded by the F13B gene. Growing evidence accumulated over decades of exhaustive research shows that not only does FXIII play major roles in both pathological extremes of hemostasis i.e. bleeding and thrombosis, but that it is, in fact, a pleiotropic protein with physiological roles beyond coagulation. However, the current FXIII genetic-epidemiological literature is overwhelmingly derived from the bleeding pathology associated with its deficiency. In this article we review the current clinical, functional, and molecular understanding of this fascinating multifaceted protein, especially putting into the same perspective its genetic landscape.

Coagulation Factor XIII Subunit A Is a Biomarker for Curative Effects and Prognosis in Malignant Solid Tumors, Especially Non-small Cell Lung Cancer

Background

The expression of coagulant factor XIII subunit A (FXIII-A) is significantly increased in some types of cancer cells and tumor-associated macrophages (TAMs). However, few studies on plasma FXIII-A in cancer patients have been conducted and have shown contradictory results, so the relationship of plasma FXIII-A with the progression and prognosis of malignant tumors is still unknown. This study explored the association of plasma FXIII-A with a curative effect and the prognosis of patients with malignant solid tumors.

Methods

We monitored plasma FXIII-A before and during systemic therapy and assessed its relationship with the curative effect and prognosis of malignant solid tumors, especially non-small cell lung carcinoma (NSCLC), by propensity-adjusted, multivariable logistic regression analysis and survival curve, in a prospective study of 1147 patients with different types of malignant solid tumors. The influencing factors of plasma FXIII-A were also analyzed.

Results

We found that D-dimer (D2) = 1 mg/L was the inflection point for the association between FXIII-A and D2: FXIII-A was significantly negatively correlated with D2 (r = -0.39, p < 0.01) and FDP (r = -0.40, p < 0.01) in D2 > 1 mg/L but uncorrelated with D2 or FDP in D2 ≤ 1 mg/L, which provided a method to find a more realistic plasma FXIII-A level. Plasma FXIII-A was positively correlated with age, platelets, lymphocytes, monocytes and carcinoembryonic antigen (CEA). It was found for the first time that plasma FXIII-A was abnormally significantly increased (FXIII-A > 150%) in post-therapy patients, especially in NSCLC and lung metastasis patients, and the incidence of FXIII-A > 150% in lung adenocarcinoma was 16 times higher than that in lung squamous carcinoma. FXIII-A > 150% proved to be an independent risk factor for disease progression in NSCLC patients (OR=5.74, 95% CI: 1.20-27.60, p = 0.029), predicting poor efficacy. The marked decrease in plasma FXIII-A (FXIII-A < 40%) was related to coagulation disorders and poor prognosis with a short survival time (median survival time of 4 months).

Conclusions

Plasma FXIII-A has the potential to be a real-time biomarker with bidirectional indicator effects to assess curative effects and prognosis in malignant solid tumors, especially NSCLC.

Expression Patterns of Coagulation Factor XIII Subunit A on Leukemic Lymphoblasts Correlate with Clinical Outcome and Genetic Subtypes in Childhood B-cell Progenitor Acute Lymphoblastic Leukemia

BACKGROUND

Based on previous retrospective results, we investigated the association of coagulation FXIII subunit A (FXIII-A) expression pattern on survival and correlations with known prognostic factors of B-cell progenitor (BCP) childhood acute lymphoblastic leukemia (ALL) as a pilot study of the prospective multi-center BFM ALL-IC 2009 clinical trial.

METHODS

The study included four national centers (n = 408). Immunophenotyping by flow cytometry and cytogenetic analysis were performed by standard methods. Copy number alteration was studied in a subset of patients (n = 59). Survival rates were estimated by Kaplan-Meier analysis. Correlations between FXIII-A expression patterns and risk factors were investigated with Cox and logistic regression models.

RESULTS

Three different patterns of FXIII-A expression were observed: negative (<20%), dim (20-79%), and bright (≥80%). The FXIII-A dim expression group had significantly higher 5-year event-free survival (EFS) (93%) than the FXIII-A negative (70%) and FXIII-A bright (61%) groups. Distribution of intermediate genetic risk categories and the "B-other" genetic subgroup differed significantly between the FXIII-A positive and negative groups. Multivariate logistic regression confirmed independent association between the FXIII-A negative expression characteristics and the prevalence of intermediate genetic risk group.

CONCLUSIONS

FXIII-A negativity is associated with dismal survival in children with BCP-ALL and is an indicator for the presence of unfavorable genetic alterations.

A novel flow cytometric method for enhancing acute promyelocytic leukemia screening by multidimensional dot-plots

Acute promyelocytic leukemia (APL) is generally characterized by t(15;17)(q24;q21). In some cases, the classic translocation cannot be identified by conventional methods, since the PML-RARA fusion protein results from complex, variant, or cryptic translocation. The diagnostic algorithm of APL starts with screening methods, such as flow cytometry (FC), followed by fluorescence in situ hybridization or polymerase chain reaction to confirm the diagnosis. Our aim was to develop a novel protocol for analyzing APL samples based on multidimensional dot-plots that can provide comprehensive information about several markers at the same time. The protocol included four optimized multidimensional dot-plots, which were tested by retrospective reanalysis of FC results in APL (n = 8) and non-APL (n = 12) acute myeloid leukemia (AML) cases. After predicting the potential position of hypergranular- and microgranular-type aberrant promyelocytes, the percentages of blast populations were examined within the gates in all AML cases. The percentage of blasts in each predefined gate was well above the cut-off value (95%) in APL cases in all tubes. In non-APL AML cases, the percentage of blasts in the same gates never reached the cut-off value in all investigated tubes, and even when it did in a single tube, the pattern was markedly different from that observed in APL cases. In conclusion, multidimensional dot-plots can be used for screening APL even in cryptic APL cases, although reproducibility across several laboratories would require standardization of antibodies and fluorochromes. This easy-to-use and quick method can support the diagnosis of APL and the prompt initiation of the appropriate treatment.

Exploring the structural similarity yet functional distinction between coagulation factor XIII-B and complement factor H sushi domains

Coagulation factor XIII (FXIII) covalently crosslinks pre-formed fibrin clots preventing their premature fibrinolysis. In plasma, FXIII circulates as a zymogenic heterotetramer composed of catalytic FXIII-A subunits, and carrier/regulatory FXIII-B subunits. FXIII-A is a well characterized component of this complex, and has been associated with several pleiotropic roles outside coagulation as well. In comparison only protective/regulatory roles towards the FXIII-A subunit have been identified for FXIII-B. Strong homology between FXIII-B and complement regulator Complement factor H suggests a putative role of FXIII-B in complement activation. In the current study we have analyzed the similarities and yet functional divergence of these two proteins using in silico sequence alignment and structural analysis. We have evaluated complement activation post reconstitution of FXIII components into FXIII deficient and CFH deficient plasma. We have also transiently expressed FXIII-B in SH-SY5Y cell lines and evaluated its effect on the endogenous complement activation. Our investigations show no effect of FXIII-B subunit on the rate of complement activation. Therefore we conclude that at a physiological level, FXIII-B subunit plays no role in the complement system, although a vestigial function in altered pathological states might still exist.

Factor XIII Subunit A Immunohistochemical Expression is Associated With Inferior Outcomes in Acute Promyelocytic Leukemia

Coagulation factor XIII subunit A (FXIIIa) intracellular expression has been described in platelets, megakaryocytes, monocytic cells, and leukemic blasts. Flow cytometric-based studies have suggested prognostic implications of FXIIIa expression, especially within the acute promyelocytic leukemia (APL) subgroup of acute myeloid leukemia (AML); however, its prognostic correlate by immunohistochemistry (IHC) is unknown. The aims of this study were to (1) define the clinicopathologic features of FXIIIa IHC-positive AML and (2) compare APL with other AML subtypes. Eighty-seven bone marrow biopsies or clot/particle preparations from our institution were evaluated with FXIIIa IHC. The study cohort consisted of bone marrow evaluations of 36 consecutive pretherapy APL, 42 selected pretherapy non-APL AML, and 9 negative staging cases. FXIIIa IHC expression was correlated with clinical and pathologic features and overall survival (OS). Leukemic blast FXIIIa cytoplasmic positivity was noted in 56% (20/36) APL and 74% (31/42) non-APL AML (P=0.10). FXIIIa IHC expression was associated with inferior OS within the APL cohort (P=0.04). No OS differences were noted in comparing FXIIIa IHC expression in all AML (P=0.17), or FXIIIa IHC expression within favorable, intermediate or adverse cytogenetic groups (P=0.14, 0.22 and 0.87, respectively). FXIIIa IHC expression is observed among a broad spectrum of AML subtypes and is not characterized by specific pathologic features. However, within the APL subgroup, FXIIIa IHC expression is associated with an inferior outcome and may be useful for additional prognostic risk stratification.

Expression of Coagulation Factor XIII Subunit A Correlates with Outcome in Childhood Acute Lymphoblastic Leukemia

Previously we identified B-cell lineage leukemic lymphoblasts as a new expression site for subunit A of blood coagulation factor XIII (FXIII-A). On the basis of FXIII-A expression, various subgroups of B-cell precursor acute lymphoblastic leukemia (BCP-ALL) can be identified. Fifty-five children with BCP-ALL were included in the study. Bone marrow samples were obtained by aspiration and the presence of FXIII-A was detected by flow cytometry. G-banding and fluorescent in situ hybridization was performed according to standard procedures. The 10-year event-free survival (EFS) and overall survival (OS) rate of FXIII-A-positive and FXIII-A-negative patients showed significant differences (EFS: 84% vs. 61%, respectively; p = 0.031; OS: 89% vs. 61%; p = 0.008). Of all the parameters examined, there was correlation only between FXIII-A expression and 'B-other' genetic subgroup. Further multivariate Cox regression analysis of FXIII-subtype and genetic group or 'B-other' subgroup identified the FXIII-A negative characteristic as an independent factor associated with poor outcome in BCP-ALL. We found an excellent correlation between long-term survival and the FXIII-A-positive phenotype of BCP lymphoblasts at presentation. The results presented seem to be convincing enough to suggest a possible role for FXIII-A expression in the prognostic grouping of childhood BCP-ALL patients.

New developments in the area of factor XIII

Coagulation factor (F)XIII is best known for its role in fibrin stabilization and cross-linking of antifibrinolytic proteins to the fibrin clot. From patients with congenital FXIII deficiency, it is known that FXIII also has important functions in wound healing and maintaining pregnancy. Over the last decade more and more research groups with different backgrounds have studied FXIII and have unveiled putative novel functions for FXIII. FXIII, with its unique role as a transglutaminase among the other serine protease coagulation factors, is now recognized as a multifunctional protein involved in regulatory mechanisms and construction and repair processes beyond hemostasis with possible implications in many areas of medicine. The aim of this review was to give an overview of exciting novel findings and to highlight the remarkable diversity of functions attributed to FXIII. Of course, more research into the underlying mechanisms and (patho-)physiological relevance of the many described functions of FXIII is needed. It will be exciting to observe future developments in this area and to see if and how these interesting findings may be translated into clinical practice in the future.