Flow Cytometric Studies on Breast Cancer

Clark, James S (1993) Flow Cytometric Studies on Breast Cancer. PhD thesis, University of Glasgow.

Abstract

This study investigated the potential of flow cytometry for assessment of both the immunology and oncology of breast cancer and explored the possibility of correlation between the two. The T cell receptor gamma/delta expression was studied in lymphocytes found in the tumour (TILs), in the tumour draining lymph nodes and in the blood. During this study the T lymphocytes were divided into CD3, CD4 and CDS phenotypic subsets to assess differences. Tumour Infiltrating Lymphocytes (TILs) were observed to have a greater median expression of CD3+ CD8+ whereas in contrast the lymph node lymphocytes (LNL) are shown to have a higher median expression of CD3+ CD4+ gamma/delta+ lymphocytes. Interestingly the majority of gamma/delta+ lymphocytes were double negative (CD4- and CD8-) which may indicate a role for this subset in immunology of breast cancer. Breast tumours often have reduced MHC class I expression, which in effect means that normal cytotoxic T cell mediated tumour killing is inhibited. Consequently other non MHC mediated killing methods, possibly mediated by the double negative gamma/delta T cell subset, may be important in tumour immunology. The immune response was assessed in a tumour invaded and a tumour free lymph node removed from the same patient. The phenotype and activation of these lymphocytes was measured by flow cytometry to study the effect of metastatic tumour on the nodal immune response. The most significant difference was noted in the T lymphocyte phenotype, with the tumour invaded lymph node having an increased percentage of CD8+ cytotoxic T cells (p<0.001) which were replaced in the tumour free node, by CD4+ T helper cells (p=0.008). The trend was clearly shown as a decreased CD4/8 ratio in the tumour invaded node, increasing significandy in the tumour free node (p<0.001). Significant changes were also observed for activation marker expression with HLA DR levels significantly higher in the tumour invaded nodes for both CD8+ T cells (p=0.023) and CD4+ T cells (p=0.036). The interleukin-2 receptor expression however was only significantly increased in the tumour invaded nodes for CD8+ T cells (p=0.029) these trends possibly being indicative of the effect of tumour invasion on the immune system. Low and high axillary nodes which had been removed from each breast cancer patient were used to assess which of the observed lymphocyte phenotype and activation differences were local and also to compare stage I and II nodal responses. The stage II patients were then further subdivided into 4 subsets on the presence or absence of metastatic tumour within these lymph nodes. Phenotypic changes were observed in the 22 stage I patients only with a significant increase in CD3+ T cell percentage in the low node (p=0.042), with a concomitant decrease in the high node. The opposite was observed for CD 19+ B cells (p=0.036), with a lower percentage in the low node. This trend was reflected in the significant decrease in the CD3/CD19 ratio (p=0.036). No significant phenotypic trends were noted for pooled stage II patients. However when the subsets of stage II patients were analysed a significant trend for T cells was noted in the subset with low node tumour invaded and the high node tumour free with a higher CD4/8 ratio in the low invaded node, decreasing in the high node (p=0.05). Lymphocyte activation trends were observed in the 22 paired stage II nodes only. The low nodes showed significantly higher percentages of CD4+ HLA DR+ lymphocytes (p=0.01) and of interleukin-2 receptor (Tac) expression on both CD8+ T cells (p=0.05) and CD4+ T cells (p<0.001). The stage II subsets showed significant changes in activation, with the low node tumour invaded and high node tumour free showing significandy higher percentages of CD8+ HLA DR+ lymphocytes in the low node compared to the high node (p=0.05). Trends of increasing interleukin-2 receptor (Tac) expression in the low node were observed for CD4+ T cells (p=0.005). A trend of increasing expression of IgG on CD 19+ B cells was observed in the subset with both low node and high node tumour free (p=0.05). The general conclusion was that the invasion of the node was reflected primarily in the HLA DR response on CD8+ (T cytotoxic) cells while distance from the tumour was reflected by the interleukin-2 receptor (tac) response on CD4+ (T helper) cells.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: Ailisa M Campbell
• Keywords: Oncology, Biochemistry
• Date of Award: 1993
• Depositing User: Enlighten Team
• Unique ID: glathesis:1993-76377
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 19 Nov 2019 14:57
• Last Modified: 19 Nov 2019 14:57
• URI: https://theses.gla.ac.uk/id/eprint/76377