Day 035 - 12 Oct 94 - Page 53
1 A. Although, I regret to say -----
2
3 Q. I do not mean to cut you short.
4 A. I regret to say those lines have blurred to a degree,
5 but yes in some context that is important.
6
7 Q. Then they go on here: "Hormones, particularly oestrogens,
8 are known to be important promoters of both animal and
9 human breast cancer, but there are conflicting reports on
10 the effect of fat on circulating levels of oestrogen,
11 other female sex hormone levels and sex hormone binding
12 globulin", SHBG, as we can call it for short. "Other
13 suggested mechanisms include modulation of immune function
14 and prostanoid synthetic pathways, and membrane lipid
15 peroxidation." Membrane lipid peroxidation is the sort of
16 damage, which I think you have proposed in your book, may
17 be done by free-radicals, is that right, eventually?
18 A. Yes, that is correct.
19
20 Q. Pausing there, is there anything within that first section
21 which seems to relate to breast cancer with which you
22 would disagree?
23 A. I am not quite certain what they mean by "conflicting
24 reports on the effects o fat on circulating levels of
25 oestrogen, other female sex hormones and sex hormone
26 binding globulin", because the literature in my reading is
27 consistent enough that I think the word "conflicting"
28 might not be justified; not to say that there are not some
29 areas of disagreement, but it has been generally shown
30 that higher-fat diets are linked with more free oestrogen,
31 less SHBG.
32
33 Q. The reference given is to a paper by Prentice and others
34 in Cancer Research 1989 which is two years before this
35 book was published. Prentice is a well-known researcher
36 in this field?
37 A. Yes.
38
39 Q. May one take it -- one has not got the reference here,
40 unfortunately -- would it be your guess that that article
41 by Prentice is what we call a review of metastudy of
42 existing evidence?
43 A. It is difficult for me to arrive at that conclusion
44 based on the title. Prentice's own work, interestingly,
45 has shown that as fat is reduced oestrogen levels are
46 significantly reduced.
47
48 MR. MORRIS: Are significantly?
49 A. Are significantly reduced, that is, as fat levels in
50 the diet are reduced, circulating oestrogen levels are
51 substantially reduced as well. I am not suggesting he
52 necessarily says so in that particular article, but his
53 work has shown that and he has reported that and it has
54 been relayed as well in publications by the National
55 Cancer Institute.
56
57 MR. RAMPTON: Then go on, the authors of this report: "In
58 bowel cancer, it has been proposed that the concentration
59 of faecal bile acids is increased by high-fat diets and
60 that secondary bile acids act as tumour promoters.
