Seeking Moby Dick Mo-99

Technetium-99m (Tc-99m) is the most used radioactive tracer with over 30 million tests per year done all over the world. When tagged to a pharmaceutical or biological marker, it helps evaluate, diagnose or manage cancer spread, blood flow and cardiac function; brain activity and thyroid disease; and detect osseous metastasis, fractures and infections (bone scan). . . Tc-99m is a metastable isotope of molybdenum-99 (Mo-99). . . Lately, Tc-99m supply chain has come under stress.

(Read the rest of the article and what is being done about the this radiotracer's shortage at maiblog)

(Picture from: Science. 2011 Jan 21;331(6015):277)

Service, R. (2011). Scrambling to Close the Isotope Gap Science, 331 (6015), 277-279 DOI: 10.1126/science.331.6015.277



(Find this post at InternetArchive here)

Webinar Report: Impact of Next Generation/Whole-Genome Sequencing on Companion Diagnostics

Biomarkers are increasingly part of pharmaceutical and clinical strategy.  By some estimates, the success rate of FDA approval of new cancer drugs is 75% if mechanism-of-action and predictive or prognostic biomarkers are clearly defined, whereas it is 25% without the biomarker information.  However, identifying new biomarkers for companion diagnosis (CDx) remains a challenge—the identification of KRAS-type biomarkers is rare, there is a double regulatory hurdle and revenue issues hamper pharmaceutical investment in this area.  Whole-genome sequencing is an important tool in the discovery of biomarkers. 

Friday Grand Rounds: Russ Altman Introduces Pharmacogenomics Database PharmGKB

Every human cell, with two sets of 23 chromosomes, contains six-billion basepairs of DNA (or three-billion per haploid genome).  Of these three-billion genomic basepairs, each individual shares 99.7% with the rest of the humanity.  It is the three-tenths of a percent that determines the differences between all of us.  This tiny percent, nevertheless, comprises of about a million positions that not only make us unique individuals, but also determine how we respond to environment, succumb to certain diseases, or respond (or not) to certain drugs.  These single nucleotide changes, scattered all over the genome, are called single-nucleotide polymorphism (SNP, pronounced snip) - for example, I may have Adenine at position X, you may have C and my friend may have G at the same position.  Since the complete sequencing of human genome in 2003, the post-genomic goal has been, to answer how this 0.3% of genome determines phenotype.  Pharmacogenomics/Pharmacogenetics (PGx) is the study of how genetic makeup correlates to responses to various drugs.  

Oncology Focused Pharmacogenomic "predictive" Biomarkers

Pharmacogenetics and pharmacogenomics (abbreviated together as PGx) are key to the future of personalized medicine.  Pharmacogenomic biomarkers provide tools to predict (a) drug response or (b) adverse drug reactions.  Such biomarkers help to maximize efficacy and minimize toxicity. 

CTing the risk of dying from lung cancer.

Is CT scan is to lung cancer what Pap smear is to cervical cancer?  Can routine CT-scan screening detect asymptomatic lung cancer and improve the odds of someone being a "lung cancer survivor."  The results of the NCI-sponsored National Lung Screen Trial (NLST) released recently, would like you to believe, yes, it is.

Can we check off thyroid cancer as a conquered disease? Maybe not!

Yesterday, I came across Carolyn Sayre's nytimes.com entry, The Rising Incidence of Thyroid Cancer.  As I scanned through the article, my brain was filled with conflicting conclusions.