An immunocapture-LC-MS-based assay for serum SPINK1 allows simultaneous quantification and detection of SPINK1 variants.

Pancreatic secretory trypsin inhibitor Kazal type 1 (SPINK1) is a 6420 Da peptide produced by the pancreas, but also by several other tissues and many tumors. Some mutations of the SPINK1 gene, like the one causing amino acid change N34S, have been shown to confer susceptibility to recurrent or chronic pancreatitis. Detection of such variants are therefore of clinical utility. So far SPINK1 variants have been determined by DNA techniques. We have developed and validated an immunocapture-liquid chromatography-mass spectrometric (IC-LC-MS) assay for the detection and quantification of serum SPINK1, N34S-SPINK1, and P55S-SPINK1. We compared this method with a time-resolved immunofluorometric assay (TR-IFMA) for serum samples and primer extension analysis of DNA samples. We used serum and DNA samples from patients with acute pancreatitis, renal cell carcinoma, or benign urological conditions. With the help of a zygosity score calculated from the respective peak areas using the formula wild-type (wt) SPINK1/(variant SPINK1 + wt SPINK1), we were able to correctly characterize the heterozygotes and homozygotes from the samples with DNA information. The score was then used to characterize the apparent zygosity of the samples with no DNA characterization. The IC-LC-MS method for SPINK1 was linear over the concentration range 0.5-1000 µg/L. The limit of quantitation (LOQ) was 0.5 µg/L. The IC-LC-MS and the TR-IFMA assays showed good correlation. The median zygosity score was 1.00 (95% CI 0.98-1.01, n = 11), 0.55 (95% CI 0.43-0.61, n = 14), and 0.05 (range 0.04-0.07, n = 3) for individuals found to be wt, heterozygous, and homozygous, respectively, for the N34S-SPINK1 variant by DNA analysis. When DNA samples are not available, this assay facilitates identification of the N34S- and P55S-SPINK1 variants also in archival serum samples.

Monitoring the treatment outcome in endometrial cancer patients by CEA and TATI.

An attempt was made to compare the usefulness of determining markers carcinoembryonic antigen (CEA) and tumor-associated trypsin inhibitor (TATI) in endometrial cancer patients in whom recurrence or distant metastasis was diagnosed in observation after treatment. The study included 316 patients aged 32-81, average age of 61 years, SD = 8.72, with diagnosed endometrial cancer, treated between 1994 and 1995 at the Oncology Center in Warsaw and then under observation from 4 months to 17 years after completion of treatment. The levels of the markers TATI and CEA were assessed from the first five serum samples taken during postoperative radiotherapy and in the initial period of observation after completed treatment. Receiver operating characteristic (ROC) curves were generated, determining the sensitivity and specificity of both CEA and TATI in patients who experienced treatment failure, i.e., recurrence and distant metastasis. Assessing the sensitivity of the marker CEA, it was found that if in the third sample, i.e., during radiation therapy, the marker level increased by more than 20 % compared with the first sample, then recurrence of cancer occurred during the observation period in 75.9 % of patients and metastatic occurred in 69.7 % of patients. In the evaluation of the marker TATI, it was found that if the level of TATI between the first and the third sample increases by 10.6 % from the initial level, then in 84.4 % (sensitivity) of cases, this means the occurrence of cancer recurrence and in 75.7 % (sensitivity) of cases, the occurrence of metastasis. The specificity of both markers is low and not useful diagnostically.

Tumor-Associated Trypsin Inhibitor (TATI) as a Biomarker of Poor Prognosis in Oropharyngeal Squamous Cell Carcinoma Irrespective of HPV Status.

BACKGROUND: We studied the role of tumor-associated trypsin inhibitor (TATI) in serum and in tumor tissues among human papillomavirus (HPV)-positive and HPV-negative OPSCC patients. MATERIALS AND METHODS: The study cohort included 90 OPSCC patients treated at the Helsinki University Hospital (HUS), Helsinki, Finland, in 2012-2016. TATI serum concentrations (S-TATIs) were determined by an immunofluorometric assay. Immunostaining was used to assess tissue expression. HPV status was determined with a combination of p16 immunohistochemistry and HPV DNA PCR genotyping. The survival endpoints were overall survival (OS) and disease-specific survival (DSS). RESULTS: A significant correlation was found between S-TATI positivity and poor OS (p < 0.001) and DSS (p = 0.04) in all patients. In HPV-negative cases, S-TATI positivity was linked to poor OS (p = 0.01) and DSS (p = 0.05). In HPV-positive disease, S-TATI positivity correlated with poor DSS (p = 0.01). S-TATI positivity was strongly associated with HPV negativity. TATI serum was negatively linked to a lower cancer stage. TATI expression in peritumoral lymphocytes was associated with favorable OS (p < 0.025) and HPV positivity. TATI expression in tumor and in peritumoral lymphocytes correlated with lower cancer stages. CONCLUSION: Our results suggest that S-TATI positivity may be a biomarker of poor prognosis in both HPV-positive and HPV-negative OPSCC.

A GRA2 minimal promoter improves the efficiency of TATi / Tet-Off conditional regulation of gene expression in Toxoplasma gondii.

A tetracycline-responsive transcription system (Tet-Off) adapted for use in Toxoplasma gondii (nicknamed TATi) is useful for molecular biological studies of this organism. Previous studies using TATi incorporated minimal promoters derived from the gene promoters for TgSAG1 or TgSAG4. The present study achieves improved activation and suppression of an integrated reporter gene in the absence and presence of anhydrotetracycline, respectively (p < 0.0001), by use of a newly derived minimal promoter based on the core promoter of TgGRA2. In comparison with the SAG1 minimal promoter, use of the GRA2 minimal promoter in stable transfectants has a 23-fold higher Signal to Noise Ratio for EYFP fluorescence in the absence or presence of anhydrotetracycline. We conclude that the performance of TATi for both activation and suppression of transcription can be markedly enhanced by incorporating a GRA2 minimal promoter.

Serum tumour associated trypsin inhibitor, as a biomarker for survival in renal cell carcinoma.

OBJECTIVE: Tumour associated trypsin inhibitor (TATI) is a peptide that is a marker for several tumours. TATI may also behave as an acute phase reactant in severe inflammatory disease. Overexpression of TATI predicts an unfavourable outcome for many cancers. This study aimed to evaluate the prognostic value of pre- and postoperative concentration of TATI in serum (S-TATI) of patients with renal cell carcinoma (RCC). MATERIALS AND METHODS: S-TATI was determined by time resolved immunofluorometric assay in preoperative and postoperative samples that were collected from 132 RCC patients, who underwent partial or complete nephrectomy in Helsinki University Hospital from May 2005 to July 2010. RESULTS: Preoperative S-TATI was significantly associated with tumour stage, lymph-node involvement, metastatic stage, Chronic Kidney Disease Stage (CKD grade), and preoperative C-reactive protein level (p < 0.05). Postoperative S-TATI was significantly associated only with CKD grade (p < 0.001). Multivariate Cox regression analysis of postoperative S-TATI, as a continuous variable, was an independent prognostic factor for overall survival (HR = 1.01, 95% CI = 1.00-1.01, p = 0.03) and cancer-specific survival (CSS) (HR = 1.01, 95% CI = 1.00-1.02, p = 0.004). CONCLUSIONS: Our data suggest that elevated postoperative S-TATI may be associated with adverse prognosis in RCC patients.

Prognostic value of the combined expression of tumor-associated trypsin inhibitor (TATI) and p53 in patients with bladder cancer undergoing radical cystectomy.

BACKGROUND: Urothelial carcinoma of the bladder is a heterogeneous disease for which reliable prognostic molecular biomarkers have not been established. OBJECTIVE: To investigate the prognostic value of tumor-associated trypsin inhibitor (TATI) expression combined with p53 expression in bladder cancer patients who have undergone radical cystectomy. METHODS: Tissue microarrays from 110 patients were analyzed immunohistochemically for TATI and p53 protein expression. Complete clinical-pathological information and follow-up data were collected. Univariable Kaplan-Meier analysis and log-rank test were performed to assess the association between TATI and p53 expression patterns with clinical outcomes. Cox's proportional hazard analysis was performed to identify potential independent risk factors for predicting disease progression and evaluate the prognostic value of combining the expression of TATI and p53 on progression-free survival (PFS) and overall survival (OS). RESULTS: TATI expression was positively correlated with favorable differentiation of bladder cancer, and lower tumor stage. p53 expression was positively related to tumor stage, tumor grade, and lymph-node invasion. Univariate Kaplan-Meier analysis revealed significant differences between TATI-positive vs. TATI-negative and p53-positive vs. p53-negative patients, regarding PFS. Multivariate analysis showed that both TATI and p53 expression were independent factors for predicting disease progression. CONCLUSION: TATI expression patterns could enhance the prognostic value of p53 overexpression on progression.

Meta-analysis of the impact of SPINK1 p.N34S gene variation in Caucasic patients with chronic pancreatitis. An update.

BACKGROUND: SPINK1 p.N34S gene variation is one of the endogenous factors which seem to be associated with chronic pancreatitis (CP). However, in literature there is no clear agreement regarding its contribution in different ethnicity and CP etiologies. AIM: To investigate the role of SPINK1 p.N34S gene variation in CP patients with European origin by means of meta-analysis. METHODS: Literature search was conducted and case-control studies evaluating Caucasian population, published between May 2007 and May 2015, were included. We also included Caucasian selected studies analyzed in previous meta-analysis. We carried out meta-analysis including all selected studies. After that, we performed two additional meta-analyses considering the incidence of SPINK1 p.N34S gene variation in alcoholic or in idiopathic CP patients vs control group. RESULTS: Twenty-five studies were included and the total number of subjects was 8800 (2981 cases and 5819 controls). The presence of p.N34S variation increased nine times the overall CP risk in population of European origin [OR 9.695 (CI 95% 7.931-11.851)]. Also, the contribution of SPINK1 in idiopathic pancreatitis [OR 13.640 (CI 95% 8.858-21.002)] was found to be higher than in alcoholic CP [5.283 (CI 95% 3.449-8.092)]. CONCLUSION: The association between SPINK1 p.N34S gene variation and CP is confirmed. Also, we confirmed that the idiopathic etiology needs a better definition by means of genetic analysis.

Claudin-5 is associated with elevated TATI and CA125 levels in mucinous ovarian borderline tumors.

BACKGROUND/AIM: Claudin proteins represent a large family of integral membrane proteins crucial for tight junction (TJ) formation and function and are abnormally regulated in several human cancers. The aim of the present study was to study the expression levels of claudin-5 in pre-malignant disease as borderline mucinous ovarian tumors. Previous reports have suggested that claudin-5 over-expression correlates with aggressive behaviour in serous ovarian adenocarcinoma, breast cancer and in pancreatic andenocarcinoma. PATIENTS AND METHODS: We investigated the expression of claudin-5 in mucinous ovarian borderline tumors and its correlation with clinico-pathological parameters and the expression of serum markers cancer antigen (CA) 125 and tumor-associated trypsin inhibitor (TATI). RESULTS: A total of 29 mucinous borderline tumor tissue samples were analyzed using immunohistochemical staining for claudin-5. An association between strong claudin-5 expression and higher serum levels of TATI (p=0.04) and CA125 (p=0.008) were found. There was also an association between claudin-5 expression and the presence of ascites (p=0.02). CONCLUSION: Changes in claudin-5 expression may play a role in malignant transformation.

TATI as a biomarker.

Tumor-associated trypsin inhibitor (TATI) [also called serine peptidase inhibitor Kazal type1, SPINK1 and, in the pancreas, pancreatic secretory trypsin inhibitor (PSTI)] inhibits trypsin and other serine proteinases and is expressed in several tissues. In addition to being a protease inhibitor, it also acts as an acute phase reactant and a growth factor. Furthermore, it may modulate apoptosis, play a role in reproduction, and be essential for normal tissue differentiation and repair. Serum TATI is elevated in many cancers and can thus be used as a diagnostic marker. Over-expression of TATI predicts an unfavorable outcome in several cancers and serum TATI can be used to identify patients at increased risk of aggressive disease. Serum TATI also increases in acute pancreatitis. Some TATI mutations predict susceptibility to recurrent or chronic pancreatitis. Recent developments in assay technologies may help in identifying mutation carriers conveniently without DNA testing. As TATI acts as a growth factor in some cancers, it has also been suggested as a therapeutic target. Taken together, assessment of TATI has several potentially important clinical applications.

Loss of SPINK1 expression is associated with unfavorable outcomes in urothelial carcinoma of the bladder after radical cystectomy.

BACKGROUND: We assessed the association of serine protease inhibitor Kazal type I (SPINK1) expression with clinicopathologic outcomes in urothelial carcinoma of the bladder (UCB) patients treated with radical cystectomy (RC). MATERIALS AND METHODS: Tissue microarrays comprising 438 consecutive UCB patients treated with RC between 1988 and 2003 and 62 cases of normal urothelium controls were evaluated for SPINK1 protein expression by immunohistochemistry (IHC). Semiquantitative evaluation was performed by 2 pathologists blinded to clinical outcomes (loss of expression: <50% cells or intensity 0-2). RESULTS: In normal urothelium, SPINK1 expression was noted in umbrella cells of 32 of 62 controls (52%); 254 RC patients (57.9%) exhibited loss of SPINK1 expression. Loss of SPINK1 expression was significantly associated with higher pathologic stages (P = 0.002) and presence of lymph node metastasis (P = 0.04). At a median follow-up of 130 months (IQR: 98.4), loss of SPINK1 expression was associated with an increased risk of disease recurrence (P = 0.02) and cancer-specific mortality (P = 0.03). On multivariable analysis that adjusted for the effects of standard clinicopathologic parameters, SPINK1 was not an independent predictor of disease recurrence (P = 0.09) or cancer-specific mortality (P = 0.12). CONCLUSIONS: Over half of UCB patients treated with RC exhibit loss of SPINK1 expression. Loss of SPINK1 correlates with features of biologically aggressive UCB. Although SPINK1 expression did not have independent prognostic value in RC patients, it may serve as a biomarker for tumor staging and may be useful as an adjunct in clinical decision-making.