Difference between Luminal A and Luminal B Subtypes According to Ki-67, Tumor Size, and Progesterone Receptor Negativity Providing Prognostic Information

Abstract

BACKGROUNDThe St. Gallen International Expert Consensus of 2011 proposes a new classification system for breast cancer based on its division into five subgroups. The criteria to identify these subtypes were recently refined at the 2013 Conference. In this respect, the authors of this paper have conducted a retrospective analysis of breast cancer subtypes, related to Ki-67 and involvement of the axillary lymph nodes (ALNs). The analysis was performed only in the cases of invasive breast cancer in the pT2 stages. The research and results of the paper have shown that investigating the value of these parameters could be of great benefit in future treatment strategies of invasive breast cancer.METHODSA retrospective analysis of breast cancer subtypes, tumor nodal metastatic staging, and histopathological grading of 108 cases has been performed according to the methods recommended and provided by the St. Gallen International Expert Consensus Report, 2011. The estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor-2 (HER2), and Ki-67 of 108 tumor samples were all investigated by immunohistochemistry according to the methods used to classify breast cancer subtypes as proposed in the St. Gallen Consensus Report, 2011. Invasive breast cancers (n = 108) were immunohistochemically classified as follows: 28 (25.92%) as Luminal A, 51 (47.22%) as Luminal B (HER2 negative), 21 (19.44%) as Luminal B-like (HER2 negative), 2 (1.85%) as HER2 positive, and 6 (5.55%) as being a triple-negative subtype.RESULTSThe conclusion was made that when Ki-67 was found to be higher, patients also showed a higher involvement in their ALNs. The chi-square test shows the difference to be significant (chi-square = 4.757; P = 0.029). Luminal B subtypes had the highest percentage (54.9%) of involvement of lymph nodes when compared to the other four subtypes. The Luminal B subtype had a higher percentage (51.4%) of involvement of lymph nodes than did Luminal A (10.7%). The chi-square test also shows the difference to be significant (P < 0.05).CONCLUSIONA combination of the Ki-67 index, HER negative tumors, PR negativity, and a low value that can be used to segregate ER positive pT2 tumors into prognostically significantly different clinical outcomes may be utilized clinically to guide patient management in accordance with these tumor characteristics.

Genomic profiling of ER + breast cancers after short-term estrogen suppression reveals alterations associated with endocrine resistance

“…A strong correlation in Ki67 expression between IHC and AQUA was observed (Spearman Rank RHO = 0.82; p<0.0001). To divide tumors into luminal A vs. B, luminal A tumors were defined as PR positive (AQUA >36) and Ki67 low (<14%) as described (42). …”

Cáncer: magnitud del problema en el mundo y en Uruguay, aspectos epidemiológicos

“…Una combinación entre el índice Ki-67 (una proteína nuclear asociada al potencial de proliferación celular) y su involucramiento con los ganglios axilares, la expresión o no del receptor-2 del factor de crecimiento epidérmico (HER2), de los receptores de estrógenos y progestágenos en los tumores ha permitido establecer al menos 4 clases de tumores con pronósticos significativamente diferentes, y ha conducido en consecuencia a la elaboración de sendas estrategias terapéuticas. Estas clases son: luminal A, luminal B, tipo Basal -HER+, y el tipo triple negativo (receptores de estrógenos y progesterona, así como HER2, negativos), los lectores interesados podrán encontrar en la literatura citada más información (44) . El cáncer de mama es desde mediados del siglo pasado la primera causa de muerte por cáncer en la mujer en nuestro país y el cáncer más frecuente en el sexo femenino (exceptuando al cáncer de piel no melanoma) (45) .…”

Noncoding RNAs in breast cancer

“…Six of these 16 basal-related miRNAs have been reported to be associated with basal-like/triple-negative breast cancer, including miR-9, miR-18 a, miR-19 a, miR-93, miR-106 b and miR-126 [141][142][143][144][145][146]. Noticeably, three miRNAs (miR-126, miR-143, miR-210) implicated in the DCIS-to-IDC transition are specifically dysregulated in basal-like IDC, suggesting that their deregulation plays a critical role in driving the progression of DCIS lesions to malignant basal-like IDC tumors (Table 2) Among luminal subtypes, luminal-B is a more aggressive subtype than luminal-A owing to low/negative expression of PR and/or HER2 overexpression, and high proliferation indicated by high Ki-67 [148]. Three miRNAs (miR-99 a, miR-100 and miR-125 b) that are involved in the transition to DCIS are specifically downregulated in luminal-B IDC.…”