Markets slid into the weekend, sending the majority of stocks lower. But Myriad Genetics (NASDAQ:MYGN) and Pfizer (NYSE:PFE) may see investor interest return after presentations at the American Association for Cancer Research meeting.

Let's look at why the confab that began Saturday in San Diego may have a beneficial impact on these two companies.

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Testing one, two, three
Ongoing late-stage clinical studies being conducted by BioMarin (NASDAQ:BMRN), AstraZeneca (NYSE:AZN), and AbbVie (NYSE:ABBV) could have big implications on advancing the opportunities tied to identifying and treating genetic mutations associated with cancer, increasing interest in Myriad Genetics, a hereditary gene testing leader.

All three drug developers are working on products that target a specific mutation to the BRCA gene that is associated with ovarian and breast cancer, and all three are using Myriad's BRACAnalysis to determine whether patients have the particular BRCA gene mutation.

Among the three BRCA therapies, AstraZeneca's Olaparib is the closest to reaching the market, as the European Union could approve the drug for ovarian cancer patients this year. BioMarin's BMN 673 entered phase 3 for BRCA 1 and BRCA 2 breast cancer patients last fall, while AbbVie's Veliparib is a bit further back in phase 2 trials. 

However, it's not just BRCA mutations that new gene therapies are targeting. As a result, Myriad is also rolling out hereditary gene tests across colon cancer, lung cancer, prostate cancer, and melanoma.

Of course, Myriad isn't alone in vying for a slice of the gene testing market. If faces competition from a slate of competitors, including diagnostics giant Quest Diagnostics. However, so far those rivals have done little to dent Myriad's growth. Myriad's sales grew over 37% year over year in the last quarter to more than $200 million.

it's likely the buzz surrounding gene testing will continue following Monday's presentation on PARP-inhibiting drugs like those being developed by AstraZeneca, BioMarin, and AbbVie.

Advancing a new breast cancer therapy
Palbociclib is one of Pfizer's most promising drugs, and while the compound has only made its way through midstage trials, results were strong enough to kick off speculation that the FDA may authorize a rolling or conditional filing that wouldn't require the drug to complete a phase 3 trial before being made available to patients.

The excitement surrounding palbociclib stems from the big unmet need for treatments for ER+ and HER2 negative breast cancer. The World Health Organization estimates 22 million cancer cases will be diagnosed annually within the next 20 years, up from 14 million a year today. ER+ or HER2 negative breast cancer will make up about 60% of those cases.

If palbociclib makes its way through regulators, it would join Xalkori and Inlyta in Pfizer's oncology portfolio. Xalkori and Inlyta sales doubled year over year in the fourth quarter to $200 million, and some industry analysts think palbociclib's total peak sales could be much bigger.

Fool-worthy final thoughts
There's little question that drug development is shifting to targeted therapies geared toward modulating protein expression, or that one of the weapons increasingly deployed in the battle against cancer will be gene analysis. That means there's likely to be a big market opportunity for Myriad, but only if it can out duel competitors like Quest.

Similarly, palbociclib could be just the blockbuster compound Pfizer needs to rejuvenate its sales, but only if it can edge out competing HER2 negative and ER+ therapies in development, including Novartis' LEE011, which entered phase 3 trials in December.