Date of Publication

6-2025

Document Type

Bachelor's Thesis

Degree Name

Bachelor of Science in Biology major in Medical Biology

Subject Categories

Cancer Biology

College

College of Science

Department/Unit

Biology

Thesis Advisor

Gerard Anthony M. Espiritu

Defense Panel Chair

James Christopher C. Chua

Defense Panel Member

Michael B. Ples
Don Ashley O. Malabana

Abstract (English)

Breast carcinoma remains as the leading cancer in women globally and locally. While great strides have been made with regard to its treatment, aggressive subtypes, particularly metastasizing breast carcinoma continue to pose significant clinical challenges. This study aims to investigate the role of microRNAs (miRNAs) in metastatic and primary breast carcinoma, identifying potential targets for therapy. RNA was extracted from formalin-fixed, paraffin-embedded (FFPE) tissues of the primary breast tumor, normal breast tissue, and lymph node metastatic lesion among nine (9) Tondo Medical Center patients with breast carcinoma with lymph node metastasis. The expression of miR-21 and miR-127 was determined using reverse transcriptase and quantitative polymerase chain reaction (qRT-PCR). Cycle threshold (CT) values were correlated with histopathologic data between the three groups. All nine (9) patients, aged between 43 to 63 years old, had primary breast carcinoma with Nottingham Histologic Score II tumors ranging from 3.0 cm to 8.0 cm. Two of the nine cases had associated in situ carcinoma. Referring to miRNA expression, miR-21 was expressed in seven primary tumors, three metastatic lymph nodes, and four adjacent normal breast tissue. Conversely, only two of the nine samples had miR-127 expression for both primary tumor and metastatic lymph node lesions, and one in adjacent normal breast tissue sample. Interestingly, two primary tumors demonstrated a potential co-expression of miR-21 and miR-127, and only one case exclusively expressed miR-127 in metastatic lymph node lesion. These findings align to existing literature indicating frequent miR-21 upregulation in malignant and adjacent tissues, suggesting its oncogenic role in tumor suppression and metastasis. Constratingly, miR-127 is expressed inadequately, implying a potential tumor-suppressive function yet remained to be dampened in cancer development. Such reinforces miR-21 as a potential target in the development of an alternative therapy. Moreover, the tumor suppressor activity of miR-127 against miR-21, particularly in primary tumor and metastatic lesions, needs further investigation.

Keywords: breast cancer, miRNA, cycle threshold, in situ carcinoma, co-expression

Abstract Format

html

Abstract (Filipino)

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Abstract Format

html

Language

English

Format

Electronic

Keywords

Breast—Cancer--Philippines--Manila; MicroRNA; Tondo Medical Center (Philippines)

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Embargo Period

8-11-2028

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Available for download on Friday, August 11, 2028

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