What is 1p/19q codeletion?

The topic of “1p/19q codeletion” is covered under following subheadings:

Introduction and Important Points #

  • Genetic marker for Oligodendrogliomas (pathognomonic for oligodendroglioma)
  • Tie-breaker’ to distinquish oligo- from astrocytomas
  • It indicates favorable prognosis
  • It is associated with better chemosensitivity (increased response to chemotherapy)
  • It is due to Loss of one arm of a hybrid chromosome is called loss of heterozygosity (LOH)
  • This is tested using FISH (fluorescence in situ hybridization)
1p 19q codeletion

What is the Incidence of 1p/19q codeletion in Oligodendrogliomas? #

  • Codeletion of 1p and 19q occurs in up to 70% of oligodendrogliomas. [2] [3]
  • This genetic signature was first noted by Reifenberger et al [5]

How is it detected? #

  • Chromosome 1p/19q codeletion is demonstrated by fluorescence in situ hybridization (FISH) [1]
  • Demonstration of 1p/19q codeletion in addition to demonstration of IDH mutation, is now necessary for the diagnosis of oligodendroglioma,
  • FISH probes do not directly demonstrate complete deletion of the entire arms of chromosomes
  • Thus, alternative molecular testing methods that probe copy number changes along entire chromosomes (gene chip arrays for example) are preferred and will limit false positive results

Clinical Significance #

Gliomas that have lost the entire short arm of chromosome 1 (1p) and the entire long-arm of chromosome 19 (19q), have 2 distinct prognostic features [4]:

  1. they grow slowly, even those that are anaplastic,
  2. they respond to DNA damaging therapies


Article Written By: Dr Sandeep Moolchandani MS, MHA, DrNB Neurosurgery

Read Similar Posts

MRI Spectroscopy : Neurosurgery Notes

Cerebral Localization in Neurosurgery- Pre and Intraoperative techniques


  1. Ferris, Sean P.; Hofmann, Jeffrey W.; Solomon, David A.; Perry, Arie (2017). Characterization of gliomas: from morphology to molecules. Virchows Archiv, (), –. doi:10.1007/s00428-017-2181-4 
  2. Jenkins RB, Blair H, Ballman KV, et al. A t(1;19)(q10;p10) mediates the combined deletions of 1p and 19q and predicts a better prognosis of patients with oligodendroglioma. Cancer Res. 2006;66:9852–9861
  3. Griffin CA, Burger P, Morsberger L, et al. Identification of der(1; 19)(q10;p10) in five oligodendrogliomas suggests mechanism of concurrent 1p and 19q loss. J Neuropathol Exp Neurol. 2006;65:988 –994.
  4. Cairncross, Gregory; Jenkins, Robert (2008). Gliomas With 1p/19q Codeletion:a.k.a. Oligodendroglioma. The Cancer Journal, 14(6), 352–357. doi:10.1097/ppo.0b013e31818d8178
  5. Reinfenberger J, Reinfenberger G, Liu L, et al. Molecular genetic analysis of oligodendroglial tumors shows preferential allelic deletions on 10q and 1p. Am J Pathol. 1994;145:1175–1190

Ask a Question or Write what do you feel about this post!!

Do more at World Surgery Forum
Explore More Surgery Topics You Like

Best Surgery Books


  1. MRCS Part A: Essential Revision Notes: Book 1
  2. MRCS Part A: Essential Revision Notes: Book 2
  3. MRCS Practice Papers Part A: Paper 1 SBAs
  4. MRCS Practice Papers Part A: Paper 2 EMQs
  5. Rush University Medical Center Review of Surgery
  6. Bailey & Love Companion Guide Mcqs & Emqs In Surgery
  7. SBA MCQs and EMQs for the MRCS Part A Pack: 2
  8. Basic Science for the MRCS: A revision guide for surgical trainees
  9. Oxford Handbook of Clinical Surgery
  10. Get Through MRCS Part A: SBAs
  11. Mrcs Module 2016 Question With Explanations For Mrcs The Best Question Series
  12. EMQs and Data Interpretation Questions in Surgery


  1. DrExam Part B MRCS OSCE Revision Guide: Book 1
  2. DrExam Part B MRCS OSCE Revision Guide: Book 2
  3. OSCEs for the MRCS Part B: A Bailey & Love Revision Guide
  4. Succeeding in the MRCS Part B Exam: Essential revision notes for the OSCE format
  5. Get Through MRCS: Anatomy 2E
  6. Clinical Anatomy: Applied Anatomy for Students and Junior Doctors by Harold Ellis
  7. Essential Radiological Anatomy for the MRCS
  8. Surgical Critical Care: For the MRCS OSCE by Mazyar Kanani and Simon Lammy
  9. Surgical Critical Care Vivas by Mazyar Kanani
  10. Mcminn’s Color Atlas of Human Anatomy
  11. Netter’s Atlas of Human Anatomy



  1. Surgery Essence By Pritesh Singh
  2. Surgery Sixer for NBE by Rajamahendran 4th ed (2019)
  3. Bailey & Love Companion Guide Mcqs & Emqs In Surgery
  4. Schwartz’s Principles of Surgery ABSITE and Board Review
  5. Surgery PreTest Self-Assessment and Review, 13th ed
  7. Surgery For PGMEE 13th Edition – 2019 by Amit Ashish


  1. Bailey & Love’s Short Practice of Surgery, 27th Edition
  2. Sabiston’s Textbook of Surgery
  3. Schwartz’s Principles Of Surgery
  4. SRB’S Manual Of Surgery


  1. Operative Techniques in Surgery by Michael W. Mulholland et al
  2. Chassin’s Operative Strategy in General Surgery
  3. Farquharson’s Textbook of Operative General Surgery, 10th Edition

"To be great, a surgeon must have a fierce determination to be the leader in his field. He must have a driving ego, a hunger beyond money. He must have a passion for perfectionism. — Donald B. Effler"

World Surgery Forum – Disclaimer
The information given on this page is for educational purposes only and should not be a substitute for professional medical advice. Do not use this information to diagnose or treat your problem without consulting your doctor. This site respects copyright and does not offer any free ebook downloads. The site and posts may contain amazon links of surgery books and products we love.
Subscribe to WSF via Email

Enter your email address to subscribe and receive notifications of new posts by email.

Join 27,829 other subscribers

Check out our Social links for regular updates

WorldSurgeryForum.net has been created by a group of Surgeons and Students, just like you. To create the best possible surgery reference and a teaching site, you can help by sharing some of your expertise, experiences, case reports, surgical images and Surgery Youtube videos. By pooling our collective knowledge and experience, we can make a real difference in how people all over the world are managed for various surgical ailments . Every new article, every case, and every image or video counts.