ALFACELL's ONCONASE Shown to Control Cancer Cell Growth.

BLOOMFIELD, N.J.--(BUSINESS WIRE)--August 13, 1998--ALFACELL Corporation (NASDAQ: ACEL) announced the results of a study published in the August 1998 issue of the journal Leukemia. The study revealed that the Company's flagship product, ONCONASE(R), regulates the fundamental molecular control mechanisms of cancer cell growth. The journal article is entitled "G(1) arrest of U937 cells by ONCONASE is associated with suppression of cyclin D3 expression, induction of p16(INK4A), p21(WAF1/CIP1) and p27(KIP) and decreased pRb phosphorylation". Human histiocytic lymphoma U937 cells treated with a novel ribonuclease, Onconase, were arrested in the G(1) phase of the cell cycle, which resulted in a significant inhibition of proliferation and apoptotic cell death. The effects were observed after 24-72 hours of incubation with the drug.

From yeast to man, all normally growing cells undergo either differentiation associated with loss of proliferative activity, or they continue to proliferate until they die, primarily through a process of programmed cell death called apoptosis. There are two major groups of protein regulators of the proliferative cell cycle machinery: a) promoters (or "accelerators") of cell cycle progression, as represented by cyclins that activate specific cyclin-dependent kinases (CDKs), and b) inhibitors (or "brakes") of cell cycle progression, as represented by several inhibitors of CDKs. Cancer can be defined as the uncontrolled growth and proliferation of cells often associated with a de-regulated pattern of expression of cyclins and CDK-inhibitors, and the deficient elimination of cells by apoptosis.

The study was conducted to further investigate prior indications of the drug's ability to perturb cell cycle progression, focusing on the patterns of expression of cyclins and inhibitors of CDKs. "This study shows that ONCONASE, when added to U937 lymphoma cells, induces very specific changes in the expression of proteins that are the key regulators of cell cycle progression", says Zbigniew Darzynkiewicz, M.D., Ph.D., Director of the Brander Cancer Research Institute of New York Medical College, a world-renowned expert on cell cycle control and a member of Alfacell's Scientific Advisory Board. "The observed ONCONASE-induced decrease in expression of cyclin D3 and an increase in expression of several inhibitors of CDKs indicate that Onconase can modulate the fundamental biological processes that become de-regulated as a result of abnormal genetic changes within cancerous cells."

ALFACELL Corporation is a leader in the development of ribonucleases (RNases) for therapeutic applications. ONCONASE, an antitumor agent, is currently being investigated in Phase III clinical trials in patients with malignant mesothelioma. Onconase is being evaluated by scientists at the National Institutes of Health (NIH) for its preclinical anti-cancer activity in a variety of tumor systems. ALFACELL is located in Bloomfield, New Jersey. The Company's common stock is traded on NASDAQ under the symbol "ACEL".

    CONTACT: ALFACELL Corporation
              Gail E. Fraser
              Chief Financial Officer, 973/748-8082