BIOLOGICAL FACTORS

RET

Which receptor tyrosine kinase gene is most commonly associated with a heterozygous loss-of-function mutation in familial Hirschsprung disease?

EDNRB or EDN3

Besides RET, which two genes that encode a receptor-ligand pair are implicated in germline mutations affecting normal gut innervation?

PDX1 (Pancreatic Duodenal Homeobox 1)

Pancreatic agenesis is linked to a homozygous germline mutation in which gene?

PRSS1 (Trypsinogen gene)

Which gene undergoes a gain-of-function mutation that makes trypsin resistant to self-inactivation, leading to hereditary pancreatitis?

SPINK1 (Serine Peptidase Inhibitor Kazal Type 1)

A loss-of-function mutation in which gene results in the absence of a crucial trypsin inhibitor?

CFTR (Cystic Fibrosis Transmembrane Conductance Regulator)

Which gene mutation leads to decreased bicarbonate secretion and protein plugging in the pancreatic ducts?

CASR (Calcium-Sensing Receptor)

What is the membrane-bound receptor that senses extracellular calcium levels and may activate trypsin if mutated?

CTRC (Chymotrypsin C)

Which protein product degrades trypsin to protect the pancreas from trypsin-related injury?

CPA1 (Carboxypeptidase A1)

Which exopeptidase is involved in regulating zymogen activation and is associated with hereditary pancreatitis?

ERBB2 (Her2-neu)

Which oncoprotein is frequently overexpressed in gallbladder carcinoma and serves as a potential therapeutic target?

TP53

Which tumor suppressor gene often undergoes a loss-of-function mutation in gallbladder carcinoma and pancreatic ductal adenocarcinoma?

KRAS

What is the most frequently altered oncogene in pancreatic cancer, participating in signaling downstream of growth factor receptors?

CDKN2A (p16)

Which frequently inactivated tumor suppressor gene in pancreatic cancer encodes proteins like p16/INK4a to regulate the cell cycle?

SMAD4 (DPC4)

Inactivation of which gene in 55% of pancreatic cancers disrupts signal transduction from the TGF-β surface receptors?

CTNNB1 (B-catenin)

Activating mutations of which oncogene lead to hyperactivation of the Wnt signaling pathway in solid-pseudopapillary neoplasms?

GNAS

Which oncogene is frequently mutated alongside KRAS in intraductal papillary mucinous neoplasms (IPMN)?

RNF43

Which tumor suppressor gene is commonly mutated in mucinous cystic neoplasms and IPMNs?

ABCG8

A common variant of which gene is associated with an increased risk of hypersecretion of biliary cholesterol and gallstone formation?

MDR3 (ABCB4)

A defect in which gene impairs phospholipid secretion, leading to the formation of primary bile duct stones?

PNPLA3

Which genetic polymorphism is a known factor for the progression of alcohol-associated liver disease and MASLD?

IL28B (CC genotype)

Which specific genetic genotype is a host factor that favors spontaneous recovery from a Hepatitis C infection?

Alcohol Dehydrogenase (ADH1)

What is the primary enzyme responsible for converting ethanol into the toxic metabolite acetaldehyde?

CYP2E1

Which enzyme is induced by chronic alcohol consumption and contributes to the conversion of ethanol to acetaldehyde?

Acetaldehyde Dehydrogenase (ALDH)

Which enzyme is responsible for the conversion of acetaldehyde into acetate?

β-glucuronidase

Which enzyme, released by bacteria like E. coli, hydrolyzes bilirubin glucuronides to promote pigment stone formation?

Enteropeptidase (Enterokinase)

Which duodenal enzyme is responsible for the initial activation of trypsinogen into trypsin?

HMG-CoA Reductase

Estrogen exposure stimulates which hepatic enzyme to increase cholesterol uptake and biliary secretion?

Trypsin

Which enzyme, once prematurely activated within the pancreas, triggers the activation of prophospholipase and proelastase?

Amylase

Which pancreatic enzyme rises within the first 24 hours of acute pancreatitis but has a short half-life?

Lipase

What is the most specific and sensitive serum marker for acute pancreatitis, remaining elevated for 8 to 14 days?

Prophospholipase and Proelastase

Which two proenzymes are activated by trypsin to degrade fat cells and blood vessels in the pancreas?

Glucuronyl-transferase

Neonatal cholestasis in Gilbert’s Syndrome is caused by a mutation in which enzyme?

HCV RNA Polymerase

The low fidelity of which enzyme leads to the genomic instability and "quasi-species" nature of Hepatitis C?

Reverse Transcriptase

Which enzyme activity, encoded within the HBV polymerase gene, uses a 3.5 kb RNA pre-genome as a template?

RNase H

DNA replicative intermediates in Hepatitis B are a result of the activity of which enzyme?

HBV DNA Polymerase

Which enzyme is the target of competitive inhibition by nucleoside and nucleotide analogs like Tenofovir?

Alpha-fetoprotein (AFP)

Which tumor marker is used for the screening and surveillance of hepatocellular carcinoma?

Carcinoembryonic Antigen (CEA)

Besides CA19-9, which serum marker is useful in evaluating pancreatic cancer in non-secretors?

CA19-9

What is the primary serum tumor marker used to monitor response to therapy in pancreatic ductal adenocarcinoma?

HBsAg (Hepatitis B Surface Antigen)

What protein makes up the external envelope of the HBV virion and is also required by the Delta agent?

HBeAg (Hepatitis B e Antigen)

Which soluble protein circulates in the serum as an indicator of high HBV replication and infectivity?

HBcAg (Hepatitis B Core Antigen)

Which antigen is associated with the HBV nucleocapsid and is found within "sanded nuclei" histologically?

Delta Antigen (HDAg)

What is the only protein produced by the Hepatitis D virus, which is surrounded by an HBsAg envelope?

E2 Protein

Which HCV envelope protein is the most variable region of the genome and the primary target of neutralizing antibodies?

VPG

Which protein is shown attached to the RNA in the structure of the Hepatitis A virus?

Albumin

The Child-Pugh score uses the serum levels of which liver-produced protein to assess operative risk?

Coagulation Factors II, VII, IX, and X

The liver produces which group of proteins whose deficiency leads to coagulopathy in cirrhosis?

Triglycerides

Fat droplets in hepatic steatosis are predominantly composed of which lipid?

Mallory-Denk Hyaline

What are the dense, eosinophilic cytoplasmic inclusions made of destroyed intermediate filaments found in steatohepatitis?

Type I Collagen

Which protein is highlighted by Masson-Trichrome stain to identify fibrosis in the portal tract or cirrhotic nodules?

Type III Collagen

Which protein provides the reticulin framework that supports the hepatic parenchyma?

Keratin 7 and Keratin 19

Which two proteins are used as immunohistochemical markers to highlight bile ducts and ductular reactions?

CD10 and p-CEA

Which two proteins are glycoproteins used as markers to highlight the bile canaliculi?

Estrogen and Progesterone Receptors

Mucinous cystic neoplasms of the pancreas characteristically express which two hormone receptors in their stroma?

Inhibin

Besides hormone receptors, the "ovarian stroma" of mucinous cystic neoplasms expresses which protein?

Aflatoxin

Which fungal metabolite is a significant environmental protein-linked toxin that causes hepatocellular carcinoma?

Transferrin/Ferritin (Iron)

Excessive deposition of which mineral protein complex in hepatocytes defines hemochromatosis?

Copper

Wilson’s disease is characterized by the toxic accumulation and deposition of which metal within hepatocytes?

Alpha-1-Antitrypsin

What is the natural protease inhibitor produced by the liver whose deficiency can lead to cirrhosis and HCC?

TGF-β (Transforming Growth Factor Beta)

Which growth factor signaling is inhibited by the loss of SMAD4 in pancreatic cancer?

PDGF (Platelet-Derived Growth Factor)

Along with TGF-β, which growth factor is produced locally to activate periacinar myofibroblasts and promote fibrosis?

Platelet-Activating Factors

Trousseau’s syndrome in pancreatic cancer is caused by the elaboration of which procoagulant factors?

Insulin, Glucagon, and Somatostatin

What three major hormones are produced by the endocrine proteins of the islets of Langerhans?

Pancreatic Polypeptide

Which protein is secreted by the endocrine pancreas alongside insulin and glucagon?

Farnesoid X Receptor (FXR)

Obeticholic acid acts as a ligand for which nuclear receptor to modulate hepatic fibrosis and lipid synthesis?

RET Receptor Tyrosine Kinase

What specific cell surface receptor is activated to regulate the development of the enteric nervous system?

Hepatocyte Receptors

HBV initiates infection by attaching to what specific structures on the host cell surface?

Acylic Nucleoside Phosphonate

Tenofovir is a nucleotide analog of which specific purine?

Guanosine Analog

Entecavir and Ribavirin are both analogs of which nucleoside?

Uridine Analog

Sofosbuvir is a prodrug that is metabolized to an active triphosphate form of which analog?

Cytosine Analog

Lamivudine is which type of nucleoside analog used to prevent vertical HBV transmission?

Adenine Analog

Adefovir dipivoxil is which type of nucleotide analog?

Inhibitor of NF-kB

What is the primary pharmacodynamic function of 5-Aminosalicylates (5-ASA) in IBD?

Phospholipase A2 and COX-2

Glucocorticoids reduce inflammation by inhibiting the gene transcription of which two enzymes?

NS5A Protein

Which HCV protein is involved in viral replication and assembly and is targeted by drugs ending in "-asvir"?

NS5B RNA-dependent RNA Polymerase

Which HCV enzyme is targeted by the drug Sofosbuvir?

NS3/4A Protease

Which enzyme is responsible for HCV polyprotein processing and is inhibited by drugs ending in "-previr"?

DNA Gyrase and Topoisomerase IV

Ciprofloxacin, used in IBD, inhibits DNA replication by binding to which two bacterial enzymes?

B-catenin

Activating point mutations of which protein are associated with acinar cell carcinoma?

GATA6 and BRD4

Epigenetic promoter hypermethylation in pancreatic cancer can lead to the overexpression of which two oncogenes?

p16/INK4a

What cyclin-dependent kinase inhibitor protein is encoded by the CDKN2A gene?

ARK

Which protein encoded by the CDKN2A gene augments the function of p53?

Acetylcholinesterase

Histologic confirmation of Hirschsprung disease often uses immunohistochemical stains for which enzyme?

Transcriptional Transactivator (X)

Which HBV protein is encoded by the X open reading frame and facilitates viral gene expression?

HBsAg

Which protein is the cornerstone of the recombinant Hepatitis B vaccine?

L-cells

Which intestinal cells release natural GLP-2 in response to luminal nutrients?

GLP-2 (Glucagon-like Peptide 2)

Teduglutide is an analog of which hormone used to treat short-bowel syndrome?

Insulin-like Growth Factor

Teduglutide stimulates the release of which trophic hormone from enteric neurons?

Octreotide

Which synthetic analog of somatostatin is the drug of choice for controlling acute variceal bleeding?

Somatostatin

Which naturally occurring hormone inhibits the release of glucagon and decreases mesenteric blood flow?

Vasopressin (Antidiuretic Hormone)

Which posterior pituitary hormone acts as a potent arterial vasoconstrictor in the treatment of varices?

Terlipressin

Which analog of vasopressin causes mesenteric artery vasospasm to lower portal pressure?

Propranolol and Nadolol

Which two proteins act as non-selective beta-blockers for the primary prophylaxis of variceal bleeding?

Carvedilol

Which drug is a non-selective beta-blocker that also has anti-alpha-1-adrenergic properties?

Ceftriaxone

Which third-generation cephalosporin is used for antibiotic prophylaxis in acute variceal bleeding?

Ursodeoxycholic Acid (UDCA)

Which bile acid decreases cholesterol content in bile and stabilizes hepatocyte membranes?

Chenodeoxycholic Acid (CDCA)

Which primary bile acid is a precursor for UDCA and was formerly used for stone dissolution?

Obeticholic Acid

Which synthetic derivative of CDCA acts as a ligand for the FXR receptor?

Lecithin

Which biliary component is decreased in the bile when the MDR3 transporter is defective?

Bile Acids

Which biliary components are produced by the liver via the CYP7A1 enzyme pathway?