Blood levels of adiponectin and IL-1Ra distinguish type 3c from type 2 diabetes: Implications for earlier pancreatic cancer detection in new-onset diabetes

Abstract

Background: Screening for pancreatic ductal adenocarcinoma (PDAC) in populations at high risk is recommended. Individuals with new-onset type 2 diabetes mellitus (NOD) are the largest high-risk group for PDAC. To facilitate screening, we sought biomarkers capable of stratifying NOD subjects into those with type 2 diabetes mellitus (T2DM) and those with the less prevalent PDAC-related diabetes (PDAC-DM), a form of type 3c DM commonly misdiagnosed as T2DM.

Methods: Using mass spectrometry- and immunoassay-based methodologies in a multi-stage analysis of independent sample sets (n=443 samples), blood levels of 264 proteins were considered using Ingenuity Pathway Analysis, literature review and targeted training and validation.

Findings: Of 30 candidate biomarkers evaluated in up to four independent patient sets, 12 showed statistically significant differences in levels between PDAC-DM and T2DM. The combination of adiponectin and interleukin-1 receptor antagonist (IL-1Ra) showed strong diagnostic potential, (AUC of 0.91; 95% CI: 0.84-0.99) for the distinction of T3cDM from T2DM.

Interpretation: Adiponectin and IL-1Ra warrant further consideration for use in screening for PDAC in individuals newly-diagnosed with T2DM.

Funding: North West Cancer Research, UK, Cancer Research UK, Pancreatic Cancer Action, UK.

Keywords: Adiponectin; Blood biomarkers; Early detection; IL-1Ra; Pancreatic cancer; Type 3c diabetes.

Figure 1

Biomarker development pathway. Biomarkers were selected via a multi-stage process using up to four independent sample sets. MS, mass spectrometry; PDAC, pancreatic cancer; CP, chronic pancreatitis; LSDM, long-standing diabetes (>3yr post-diagnosis of DM); NOD, new-onset diabetes (<3 yr post-diagnosis of DM).

Figure 2

Serum adiponectin measured in three independent diagnostic cohorts. Serum levels of adiponectin are unchanged in PDAC regardless of diabetes status (a) and are elevated in PDAC and PDAC-DM compared to long-standing diabetes (b) and new-onset T2DM (NOD) (c). Adiponectin shows a moderate but significant negative correlation with BMI across all sample groups, with (rs(143)= -0.359, p<0.0001 (d). The median and interquartile range are shown for each group. p-values were calculated using the Mann–Whitney U test, adjusted for multiple comparisons with the Holm-Bonferroni method. PDAC, pancreatic cancer; PDAC-DM, pancreatic cancer-related diabetes; LSDM, long-standing diabetes (>3yr post-diagnosis of DM); NOD, new-onset diabetes (<3yr post-diagnosis of DM).

Figure 3

Plasma and serum IL-1Ra measured in four independent cohorts. IL-1Ra is upregulated in patients with PDAC and PDAC-DM compared to those with T2DM, regardless of DM duration (a, b). Upregulation of IL-1Ra is observed up to 12 months prior to diagnosis as shown in pre-diagnostic training and validation serum samples (c). The median and interquartile range are shown for each group. p-values were calculated using the Mann–Whitney U test, adjusted for multiple comparisons with the Holm-Bonferroni method. PDAC, Pancreatic cancer; PDAC-DM, pancreatic cancer-related diabetes; LSDM, long-standing diabetes mellitus; NOD, new-onset diabetes mellitus; HC, healthy controls.

Figure 4

Blood levels of adiponectin and IL-1Ra measured in T3cDM and T2DM individuals (Set 3) and associated receiver operator characteristic (ROC) curve analyses. Serum levels of adiponectin (a) and plasma levels of IL-1Ra (b) are significantly elevated in patients with T3cDM (●=PDAC- and ▲=CP-related) compared to those with T2DM (adiponectin: n=33 PDAC-DM, n=15 CP-DM, IL-1Ra: n=28 PDAC-DM, n=15 CP-DM). In combination, serum adiponectin and plasma IL-1Ra achieved an AUC of 0.90 (95% confidence interval (CI): 0.83-0.97) in distinguishing T3cDM from T2DM (n=37 and 30, respectively), with an optimal sensitivity of 83.7% (CI: 68.0-93.8%) and a specificity of 90.0% (CI: 73.5-97.9%) (c). In the distinction of T3cDM from among individuals with NOD (n=37 and 12, respectively), the combined markers achieved an AUC of 0.91 (CI: 0.84-0.99) with optimal sensitivity and specificity of 83.7% (CI: 64.9-92.0%) and 100.0% (CI: 73.6-100.0%), respectively (d). For A and B, the median and interquartile range are shown for each group. T3cDM, type 3c diabetes mellitus; T2DM, type 2 diabetes mellitus; NOD, new-onset diabetes mellitus; AUC, area under the curve.

Figure 5

Serum CA19-9 measured in two independent diagnostic cohorts. In training (a) and validation (b) (Sets 2 and 3) serum CA19-9 levels were significantly elevated in PDAC, regardless of DM status, compared to all other controls (p<0.0001). No difference in CA19-9 level was observed between PDAC-DM and PDAC. In non-cancer controls, CA19-9 was significantly elevated in LSDM compared to healthy controls (p=0.03 and p=0.001 in Sets 2 and 3, respectively), however, no significant upregulation was observed between NOD and HC. For a and b, the median and interquartile range are shown for each group. PDAC, pancreatic cancer; PDAC-DM, pancreatic cancer-related diabetes; CP, chronic pancreatitis; CP-DM, chronic pancreatitis-related diabetes; LSDM, long-standing diabetes (>3yr post-diagnosis of DM); NOD, new-onset diabetes (<3yr post-diagnosis of DM).