Over the course of the last hundred years, science triumphed over many of the diseases and illnesses that had plagued populations past: It attacked influenza with antibiotics, vaccinated polio and vanquished smallpox. Today, cancer tops the list of research priorities, with billions of dollars poured into its study on an annual basis.

While a cure for the killer continues to elude us, biotech companies are more determined than ever to find effective treatments -- and investors and venture capital firms are placing bets on who will win the race.

In the first quarter of 2010 alone, biotech raised almost $825 million in venture capital deals, making it the leading industry in dollars invested over the trailing 12-month period.

But that's pocket change when you consider how much a cancer cure is actually be worth -- a study by the Chicago Graduate School of Business puts it at $50 trillion for Americans alone. Double that figure if you factor in the rest of the industrialized world. Even smaller advancements can have a profound impact, according to the study: a 1% reduction in mortality rates is the economic equivalent of $500 billion.

That's why Wall Street gets so excited over treatments like Dendreon's (Nasdaq: DNDN) Provenge. Promising to prolong mortality in advanced prostate cancer patients, the drug sparked a 900% run-up in the company's stock during 2010.

And then there's Gereon Corporation's (Nasdaq: GERN) imetelstat sodium, aka GRN 163L, which could be the next market darling. It uses embryonic stem cells to fight cancer in its early stages, disrupting the process that causes cancer to grow uncontrollably.

These are just two of the many cancer drugs being developed by biotech companies. So what other cancer stocks are investors taking seriously? For clues, we looked to the options market, to see which stocks had seen dramatic decreases in their put/call ratios. This indicates a spike in call volume, a sign of bullishness around a stock.

Here's a list of five stocks that have seen rising call volume over recent weeks. Options traders seem to be getting excited by these names -- what do you think? (Click here to access free, interactive tools to analyze these ideas.)

Options data sourced from Schaeffer's. The list has been sorted by the change in the Put/Call ratio.



Put/Call Change Between Jan. 26-Feb. 8

Allos Therapeutics (Nasdaq: ALTH)

Focuses on developing and commercializing anti-cancer therapeutics

Decreased from 0.37 to 0.26

China Medical Technologies (Nasdaq: CMED)

This Chinese biotech company sells an imaging analysis system that enables medical practitioners to visualize and locate DNA sequences in human cells for identifying various cancers.

Decreased from 0.94 to 0.83

Delcath Systems (Nasdaq: DCTH)

Develops and manufactures devices to administer high dose chemotherapy. It focuses on the development of the Delcath PHP System, a Phase III clinical trial product, which isolates the liver from the patient's general circulatory system and delivers high dose of melphalan hydrochloride or other therapeutic agents directly to the liver.

Decreased from 0.49 to 0.38

Myriad Genetics (Nasdaq: MYGN)

The company markets BRACAnalys for assessing a woman's risk for breast and ovarian cancer; COLARIS for assessing a person's risk of developing colorectal cancer, and MELARIS, which assesses a persons risk of developing melanoma.

Decreased from 0.32 to 0.28

ZIOPHARM Oncology (Nasdaq: ZIOP)

Focuses on the development and commercialization of a portfolio of cancer drugs in North America.

Decreased from 1.05 to 0.88

Interactive Chart: Press Play to compare changes in analyst ratings over the last two years for the stocks mentioned above. Analyst ratings sourced from Zacks Investment Research. Note: The numbers on top of items represent the forward P/E ratio, if available.

Kapitall's Eben Esterhuizen and Alicia Sellitti do not own shares of any companies mentioned.

Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.