The Coordinating and Data Management Center (CDMC) at MD Anderson Cancer will be responsible for the coordination and data management for the Evaluation of a mixed meal test for Diagnosis and characterization of Type 3c diabetes mellitus secondary to pancreatic cancer and chronic pancreatitis (DETECT), which is part of the NIH U01 funded Consortium for the Study of Chronic Pancreatitis, Diabetes, and Pancreatic Cancer (CPDPC). Similar to all studies that will be coordinated and managed by the CDMC, no patient enrollment will occur at MDACC. All patient recruitment will occur at external sites that are a part of the CPDPC, which are listed in the appended DETECT protocol. The data management systems, auditing, and monitoring effort are supported by the CDMC.

Objectives:

1. Evaluate the pancreatic polypeptide response following a standardized mixed meal in new onset diabetes associated with PDAC (particularly with a proximal tumor) and chronic pancreatitis vs. T2DM.
2. Evaluate the insulin and glucagon response following a standardized mixed meal in new onset diabetes associated with PDAC and chronic pancreatitis vs. T2DM.
3. Evaluate the incretin response following a standardized mixed meal in new onset diabetes associated with PDAC and chronic pancreatitis vs. T2DM.
4. Explore the differences in analytes from Objectives 1-3 in a cohort of subjects with the same diseases and long-standing DM or normoglycemia.
5. Evaluate differences in fasting levels of insulin and novel biomarkers in pancreatic cancer compared to chronic pancreatitis and T2DM.
6. Explore the metabolic alterations (including pancreatic polypeptide response and insulin secretion) in diabetes associated with pancreatic surgery for chronic pancreatitis.

Inclusion Criteria:

• All Participants must sign an informed consent indicating that they are aware of the investigational nature of this study. Participants must have signed an authorization for the release of their protected health information.
• Participants must be ages ≥30 and <85.
• Participants must have a diagnosis of one of the following based on study definitions;
• New Onset Diabetes (<3 years) in participants with Pancreatic Cancer (PDAC);
• New Onset Diabetes (<3 years) in participants with Chronic Pancreatitis;
• New Onset Diabetes (<3 years) in participants without Pancreatic disease (i.e., T2DM)
• Long standing T2DM (≥3 years) without Pancreatic disease
• Long standing diabetes (≥3 years) in participants with PDAC
• Long standing diabetes (≥3 years) participants with chronic pancreatitis
• non-diabetic participants with PDAC
• non-diabetic participants with chronic pancreatitis
• non-diabetic controls without Pancreatic disease

Exclusion Criteria:

• Participants must not have any significant medical illnesses (including diabetes) that in the investigator's opinion cannot be adequately controlled with appropriate therapy or would compromise the Participant's ability to tolerate study interventions.
• Diabetes not stable enough to permit holding of diabetes medications in Participants undergoing mixed meal tolerance testing.
• Participants taking higher doses of insulin (≥0.75 unit/kg/day). [Criterion is not applicable for PDAC Participants undergoing fasting only blood collection]
• Participants in the non-pancreatic disease subgroup on longer acting agents, including thiazolidinediones and once-weekly GLP-1 agonists (Bydureon [exenatide], Ozempic [semaglutide], Trulicity [dulaglutide]). [Criterion is not applicable for Participants in the CP and PDAC groups].
• Participants currently receiving oral steroid medications.
• Hospitalization for acute pancreatitis within 2 months before study visit. [Criterion is not applicable for PDAC Participants undergoing fasting only blood collection]
• The presence of a symptomatic cyst in Participants with CP. [Criterion is not applicable for PDAC Participants undergoing fasting only blood collection; this includes cancer arising from a mucinous cystic lesion].
• Any Participant with a known pancreatic cancer histologic subtype other than adenocarcinoma (e.g., Participants with pancreatic neuroendocrine tumors are excluded).
• Previous pancreatic surgery (including total pancreatectomy, pancreaticoduodenectomy, distal pancreatectomy, pancreaticojejunostomy, enucleation, or Frey procedure). [Criterion is not applicable for CP Participants with diabetes who have a history of pancreaticoduodenectomy, pancreaticojejunostomy, distal pancreatectomy, or Frey].
• Previous treatment for pancreatic cancer, including chemotherapy or radiation.
• Previous vagotomy or gastric surgery, including endoscopic gastric reduction procedures. [Criterion is not applicable for PDAC Participants undergoing fasting only blood collection].
• Previous diagnosis of gastroparesis. [Criterion is not applicable for PDAC Participants undergoing fasting only blood collection].
• Participants on treatment for any cancer (except non-melanoma skin cancer or carcinoma in-situ of the cervix).
• Allergy or intolerance to ingredients in Boost drink in Participants undergoing mixed meal testing (see Appendix 13.9) [Criterion is not applicable for PDAC Participants undergoing fasting only blood collection].

Participants recruited from external sites.