Which is most common site of Ca pancreas?

Ans: a (Head) Ref: Robbins, 7th ed, p. 950Most commonly Ca pancreas arises from head.- Head-60%- Body - 15%- Tail - 5%- Diffusely involves the gland-20%Carcinoma of pancreas are usually hard, stellate, grey - white poorly defined masses.Two features are characteristic of pancreatic cancer.- Highly invasive.- It elicits an intense nonneoplastic host reaction composed of fibroblasts, lymphocytes & extracellular matrix.tdesmoplastic response)Trousseau sign - Migratory thrombophlebitis due to elaboration of platelet - aggregating factors & procoagulants from the tumor or its necrotic products.Common sites- Insulinoma - All over pancreas- Pseudocyst - Body & tail- VIPomas - Tail- Glucagonoma - Tail (> 1 million islets => max in tail)- Somatostatinoma - HeadMolecular cacrcinogenesisK- ras gene (chromosome 12p)- Most frequently altered oncogene in Ca pancreas,p 16 (chromosome 9p) - Most frequently inactivated tumour suppressor gene in pancreatic cancer.SMAD 4 (chromosome 18q) - Tumour suppressor gene is inactivated in 55% of pancreatic cancers.p53 - (chromosome 17p) - Inactivation of the p53 tumour suppressor gene is seen in 50 - 70% of pancreatic cancers.