Soy Consumption and Histopathologic Markers in Breast Tissue Using Tissue Microarrays

Abstract

This study examined the relation of soy intake with hormonal and proliferation markers in benign and malignant breast tissue using tissue microarrays (TMAs). TMAs with up to 4 malignant and 4 benign tissue samples for 268 breast cancer cases were constructed. Soy intake in early life and in adulthood was assessed by questionnaire. The TMAs were stained for estrogen receptor (ER) α, ERβ, progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2/neu), proliferating cell nuclear antigen (PCNA), and Ki-67 using standard immunohistochemical methods. Logistic regression was applied for statistical analysis. A higher percentage of women showed positive marker expression in malignant than in benign tissue. With one exception, HER2/neu, no significant associations between soy intake and pathologic markers were observed. Early life soy intake was associated with lower HER2/neu and PCNA staining of malignant tissue. In benign tissue, early life soy intake showed higher ER and PR expression, but no difference in proliferation markers. The results of this investigation provide some assurance that soy intake does not adversely affect markers of proliferation. TMAs were shown to be a useful tool for epidemiologic research.

ACKNOWLEDGMENTS

The breast pathology study and the nested case-control study were funded by grants from the National Cancer Institute (R21 CA1080250 and R01 CA85265). The Multiethnic Cohort Study has been supported by USPHS (National Cancer Insitute) Grant R37 CA 54281 (PI: Dr. L. N. Kolonel). We are grateful to the study participants and to the staff of the Hawaii Tumor Registry for their support. We thank Hugh Luk for the preparation of the TMAs, Hermina Borgerink for the staining of the TMAs, and Joseph Finley for the assessment of stains.

Notes

^a Abbreviations are as follows: TMA, tissue microarrays; HRT, hormone replacement therapy. Means ± SD unless stated otherwise.

^a Abbreviations are as follows: ER, estrogen receptor; PR, progesterone receptor; HER2/neu, human epidermal growth factor receptor 2. Odds ratios (OR) and 95% confidence interval (95% CI) were obtained by logistic regression and adjusted for ethnicity, age, BMI, and HRT use; totals may differ due to variations in the number of readable cores.

^b Categories for ERα, ERβ, PCNA, and HER2/neu: Category 1 = no stain or < 10% stain and Category 2 = ≥ 10% stain.

^c Categories for PR and Ki-67: Category 1 = no stain and Category 2 = any stain.

^d Category 1 = Grade 1 and 2; Category 2 = Grade 3.

^e Category 1 = in situ and localized; Category 2 = regional.

^a Abbreviations are as follows: OR, odds ratio; CI, confidence interval; ER, estrogen receptor; PR, progesterone receptor; HER2/neu, human epidermal growth factor receptor 2; PCNA, Proliferating cell nuclear antigen. ORs were obtained by logistic regression and adjusted for ethnicity, age, body mass index, and hormone replacement therapy use; totals may differ due to variations in the number of readable cores.

^b Categories for ERα, ERβ, PCNA, and HER2/neu: Category 1 = no stain or < 10% stain and Category 2 = ≥ 10% stain.

^c Categories for PR and Ki-67: Category 1 = no stain and Category 2 = any stain.