Document wqad9V3ZxRZenG8nO8L5GZGBE

NEWS RELEASE DRAFT -- 11/14/75 CHICAGO, Nov..19 -- Monsanto Company today announced that a newly issued scientific report, commissioned by the St. Loujjis-based company,^does_afitco^f^w(^the presence of malignant liver tjumors In the tissues of experimental rats fed polychlorinated , ^1/j `f**- biphenyl (PCB) dielectric fluld,^,^ conclusion that^had been preKlwfoly ueaclieiTend widely reported by Dr. Renate D. Kimbrough of the |Center for Disease Control of the U.S. Public Health Service in Atlanta---------------------- ---------------------------------------------- - The Monsanto-sponsored report, a re-evaluation of Dr. Kimbrough's work, is titled, "Histophathological Re-evaluation of Tisfues from Sherman Rats Fed Aroclor 1260, and is authored by Dr. P. Pour, M.D. of the prestigious Eppley Institute for Research in Cancer of the University of Nebraska Medical Center at Omaha. In her study, Dr. Kimbrough reported that when Sherman strain female rats were fed 100 parts per million of PCB (Aroclor 1260) ;:or about 21 months, 170 of the 184 experimental animals developed neoplastic lesions (precursors of malignant tumors) and 26 of :hese lesions were further identified in her report as being hepato:ellular carcinomas (malignant liver tumors). During his re-evaLuation, Dr. Pour saw thesamelesions but identified them as beiig hyperplastic oi/p<5n-tumorous^y ' -more- MONS 059020 --2 In his discussion, Dr. Pour commented, `By going through the material from Dr. Kimbrough's experiment and by comparison of varLous lesions In treated and untreated rats, I gained the strong impression that many, detectable alterations represented a degenerative and reparative, rather than a neoplastic process." The Eppley Institute researcher further reported that he observed 20 cases of abnormal lesions which presented such structural criteria as to be considered precursors to tumors, although a most significant criteria for malignancy -- namely the invasion -- was missing and the sign of ongoing toxic, degenerative and regenerative processes In the rest of the tissue was evident. "At present, the statement that these lesions may have metastasized (progressed) if the treatment had been continued is as nuch as unreliable as the possibility that they might have regressed If the animals would have been kept longer or for life," he stated. "In summary," he reported, "It Is difficult at present to conclude whether or not some of the examined lesions represent a malignant lesion, because of the lack of Invasion and metastases. In the case of such organs, as the liver with Its marked tendency toward regeneration, it Is, in my opinion, difficult and sometimes impossible to distinguish between regeneration, hyperplasia and neoplasia, particularly when the tissue is continuously exposed to a tokic substance." -more- HONS 059021 --3 Quoting further from Dr. Poor's report, he wrote fa* \ this context, Dr./Kimbrough's study seems of particular Interest, polychlorinated compounds may be retained In Jthe body, higher concentrations for several months after feeding has been shopped. This finding may explain the continuing degenerative and regenerative processes in/the livers of most experimental rats, even__wo months after<^Aroclor'was removed^from the diet. One should also bear In mind that some animal strains' may rea:t more specifically to a compound because of common endogenaus diseases, as in the case of the Sherman rats used in this experiment which tend toward spontaneous liver lesions. "In my opinion," he concluded, "many of the lesions induced^ were of a degenerative nature, and without further studies, the induced liver lesions could not be definitely designated as neoplasia (tumorous). -0O0- HONS 059022