PROGENSA(R) PCA3 Assay Can Help Predict Outcome of Initial Prostate Biopsies, According to Study Presented at Leading Urology Meeting

SAN DIEGO, April 22, 2010 - — Data Also Suggest that PCA3 Scores May Indicate Prostate Cancer
Aggressiveness –

Gen-Probe's (Nasdaq: GPRO) PROGENSA(R) PCA3 assay can help predict the
outcome of initial prostate biopsies in men suspected of having prostate
cancer, according to a study of the molecular urine test presented in a
scientific poster last week at the 25th annual European Association of
Urology (EAU) Congress in Barcelona, Spain.

PCA3 is a gene that is highly over-expressed in more than 90% of prostate
cancers.

"Previous studies have demonstrated the clinical utility of PCA3 testing
in guiding repeat biopsy decisions," said Professor Alexandre de la Taille of
Hopital Henri Mondor in Paris, France. "This study is the first to show that
the PROGENSA PCA3 assay also can help determine whether a man suspected of
having prostate cancer should undergo an initial biopsy. In addition, the
study showed that PCA3 scores may indicate prostate cancer aggressiveness in
this group of men."

In the multi-centre study, PCA3 testing was performed on urine samples
from 516 men with prostate specific antigen (PSA) levels between 2.5 and 10
ng/mL who were scheduled for an initial prostate biopsy. Approximately 40% of
these biopsies were positive. Key study results included:

    - The diagnostic accuracy of the PROGENSA PCA3 test, as measured by a
      statistical technique known as AUC ROC, was maximized by using a PCA3
      score of 35 as the cut-off between normal and elevated levels. At this
      cut-off, the assay had a sensitivity of 64%, a specificity of 76%, and
      an AUC ROC of 0.761.
    - The diagnostic accuracy of the PCA3 test was statistically superior to
      that of serum total PSA (P<0.0001), PSA density (P=0.0232) and % free
      PSA (P<0.0001).
    - Men with PCA3 scores above 35 were 2.7 times more likely to have a
      positive biopsy than men with PCA3 scores below 35 (P<0.0001).
    - The higher the PCA3 score, the greater the probability of a positive
      biopsy. For example, cancer was diagnosed in only 20% of men with very
      low PCA3 scores (N=56), but in 78% of men with very high PCA3 scores
      (N=54).
    - PCA3 scores correlated with measures of prostate cancer aggressiveness.
      Specifically, mean PCA3 scores were statistically higher in men with
      Gleason scores greater or less than 7 (P<0.0001), in men with >33%
      positive biopsy cores (P<0.0001), and in men with "significant" versus
      "indolent" cancers, as measured by Epstein criteria (P=0.0016).

About Prostate Cancer and PCA3

According to the European Prostate Cancer Coalition, prostate cancer is
one of the most common cancers among European men. More than 300,000 new
cases of prostate cancer are diagnosed annually in the European Union, and
more than two million Europeans are living with the disease.

PCA3 is a gene that is highly over-expressed in more than 90% of prostate
cancers, and that can be quantified in urine specimens following a digital
rectal examination. Studies have shown that because PCA3 is highly specific
for prostate cancer, it predicts the results of repeat biopsies more
accurately than traditional prostate-specific antigen (PSA) testing.

Data from approximately 30 peer-reviewed publications suggest that PCA3
testing, when used with other patient information, may help address some of
the well-known challenges urologists face when identifying prostate cancer,
such as identifying clinically relevant cancers that need to be treated while
minimizing unnecessary biopsies.

Gen-Probe's PROGENSA PCA3 assay, which has been CE-marked for sale in the
European Union, is the first urine-based molecular diagnostic assay for
prostate cancer.

In August of 2009, Gen-Probe initiated a clinical trial intended to
secure U.S. regulatory approval of the PROGENSA PCA3 assay, and the Company
remains on track to file a Premarket Approval Application later this year.
Gen-Probe is seeking U.S. regulatory approval to use the assay on its
semi-automated instrument system to test urine samples from men who
previously have had a negative prostate biopsy.

For more information about the PROGENSA PCA3 assay, visit
www.PCA3.org.

About Gen-Probe

Gen-Probe Incorporated is a global leader in the development, manufacture
and marketing of rapid, accurate and cost-effective molecular diagnostic
products and services that are used primarily to diagnose human diseases,
screen donated human blood, and ensure transplant compatibility. Gen-Probe
has approximately 27 years of NAT expertise, and received the 2004 National
Medal of Technology, America's highest honor for technological innovation,
for developing NAT assays for blood screening. Gen-Probe is headquartered in
San Diego and employs approximately 1,300 people. For more information, go to
www.gen-probe.com.

Caution Regarding Forward-Looking Statements

Any statements in this press release about Gen-Probe's expectations,
beliefs, plans, objectives, assumptions or future events or performance are
not historical facts and are forward-looking statements. These statements are
often, but not always, made through the use of words or phrases such as
believe, will, expect, anticipate, estimate, intend, plan and would. For
example, statements concerning new products, potential regulatory approvals,
customer adoption, and results of future clinical studies are all
forward-looking statements. Forward-looking statements are not guarantees of
performance. They involve known and unknown risks, uncertainties and
assumptions that may cause actual results, levels of activity, performance or
achievements to differ materially from those expressed or implied. Some of
the risks, uncertainties and assumptions that could cause actual results to
differ materially from estimates or projections contained in the
forward-looking statements include but are not limited to: (i) the risk that
results from the U.S. clinical trial of our PCA3 test will not be favorable;
(ii) the risk that our PCA3 test will not be approved by FDA for marketing in
the U.S. in the timeframes we expect, if at all; (iii) the possibility that
the market for the sale of our PCA3 product may not develop as expected; (iv)
the risk that we may not be able to compete effectively with other tests for
prostate cancer; (v) the risk that we may not be able to maintain our current
exclusive license concerning PCA3; and (vi) the risk that our third party
distributors may not distribute our products effectively. The foregoing
describes some, but not all, of the factors that could affect our ability to
achieve results described in any forward-looking statements. For additional
information about risks and uncertainties Gen-Probe faces and a discussion of
the Company's financial statements and footnotes, see documents filed with
the SEC, including the most recent annual report on Form 10-K and all
subsequent periodic reports. We assume no obligation and expressly disclaim
any duty to update any forward-looking statement to reflect events or
circumstances after the date of this news release or to reflect the
occurrence of subsequent events.

Contact:

    Michael Watts
    Vice president, investor relations and
    corporate communications
    +1-858-410-8673

Michael Watts, vice president, investor relations and corporate communications of Gen-Probe Incorporated, +1-858-410-8673