Question and Answer Discussion 
Dr. Brown: We have time for a few questions. 
Question: Bob, did you say that 77 percent of the fish that you collected had 
cancer? 
R. Murchelano: No. I said that 77 percent of the fish in Boston Harbor have 
vacuolated hepatic parenchymal cells. Because I believe that the origin of the neoplastic 
cells is related to the vacuolated cells, then there is a potential for many more fish with 
liver cancers than has been noted. 
Question: You have shown us a string of precursors to the development of 
hepatic carcinomas. 
R. Murchelano: No, not necessarily. I showed you a string of precursors which 
are implicated in studies of experimental carcinogenesis in rodents. I believe that the 
vacuolated cell is associated in some way with neoplastic cells. The winter flounder have 
other lesions similar to those of rodents. There is some speculation as to whether these 
other lesions, the basophilic and eosinophilic foci, and the hepatocellular adenoma, are 
steps in the transition to the carcinoma. No one knows that for certain. 
Question: Have residue analyses been performed on these fish? 
R. Murchelano: Leigh mentioned that analyses have been conducted for PCBs 
on livers and flesh; that is it so far. I have bile stored that I want analyzed as soon as 
possible. I also have gonadal tissue stored for analysis. 
Question: Does the incidence of cancer vary with age in Boston Harbor? 
R. Murchelano: I did not tell you about the internal bias I used during 
sampling. I biased my collection for fish over 35 cm in length. I did that for two reasons. 
One, if induction requires a long latency period, as is well known in some cancers, the 
longer the time, the better. Second, it is well-known that immune mechanisms, both 
cellular and humoral, are compromised with age. I do not want to convey that I have 
exhaustively studied this lesion. The only thing that has been done so far is a morphologic 
study. There is a lot more that must be done. 
Question: Do you know anything at all about the length of life of these fish 
versus some that don't have the tumor? 
R. Murchelano: No. Leigh may have mentioned something about that, but I do 
not know how life span may be compromised. 
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