Breast cancer laterality and molecular subtype likely share a common risk factor

Abstract

BackgroundTo investigate the epidemiological features of breast cancer laterality and molecular subtypes in southern China.Materials and methodsA total of 2,049 cases who were diagnosed with unilateral breast cancer in the past 5 years were classified based on laterality and molecular subtypes. Molecular subtypes were defined in accordance with the 2013 St. Gallen recommendations.ResultsBreast cancer was more likely to be diagnosed in the left breast than in the right at a rate of around 5%. In the case of invasive carcinomas, the right breast was more commonly affected than the left in young (<40 years old) patients (left-to-right [L:R] ratio 0.80, 95% CI 0.65, 0.98), whereas the opposite trend was found in old (≥40 years old) patients (L:R ratio 1.06, 95% CI 1.02, 1.73). Except for invasive mucinous and invasive medullary breast cancers, the other histological types occurred more frequently on the left side than on the right. In situ cancer with a defined subtype was likely to be diagnosed as luminal B(HER-2+). Except for invasive medullary and invasive nonspecific cancers, other invasive carcinomas with a defined subtype were most likely to be diagnosed as luminal B(HER-2−). The age of ≥40 years was a risk factor for luminal B(HER-2+), and a significant correlation was present between the right breast and luminal B(HER-2+).ConclusionWe explored the risk factors of breast cancer laterality and various molecular subtypes and found that age may be a predictor of breast cancer laterality. We found that age and laterality are the probable risk factors of the luminal B(HER-2+) type of breast cancer. These results provide a basis for the epidemiological characterization of breast cancer.

Nomogram for Predicting Overall Survival and Assessing the Survival Benefit of Adjuvant Treatment in pT1-2N0M0 Triple-Negative Breast Cancer: A Surveillance, Epidemiology, and End Results-Based Study

“…Notably, breast cancer in female is more likely to occur in the left breast than in the right (19). This finding has gained the attention of many researchers and numerous hypotheses have been proposed to account for the left-side dominance of breast cancer, but none have been uniformly accepted or confirmed (20,21). In this study, we found that left-side dominance was also a risk factor for pT1-2N0M0 TNBC, which has not been reported previously.…”

Is CD 44 really a marker of breast cancer metastasis or is nefarious in its nature

“…11 Cheng et al in 2018 observed that left sided breast cancer was approximately 5% more than the right breast. 12 Uyisenga et al in 2020 observed bilateral breast cancer in some patients. 13 Majority of the cases of breast carcinoma in our study had upper outer quadrant (55.7%) involvement followed by central (18.1%) cases, lower inner quadrant (14.9%), lower outer quadrant (8.6%) and upper inner quadrant (2.7%).…”

Is laterality in breast Cancer still worth studying? Local experience in Bahrain

“… Not Applicable Left-side breast has slightly larger size Roychoudhuri R et al, 200 6[ 4 ]. Breast laterality ratio is 1.07 Not Applicable - Higher tissue mass in left-side breast which leads to increased cancer incidence Cheng SA et al, 201 8[ 5 ]. Laterality ratio in age < 40 years is 0.80 and in age > 40 years is 1.06 -Invasive carcinomas commonly affect the right-side breast at younger ages (< 40 years old).…”

“…It has been postulated that right-handed patients examine their left-side breast and axilla more accurately than their right-side breast and axilla. This leads to an earlier discovery of smaller breast lesions in their left-side breast compared to the right-side breast [ 1 , 2 , 5 ]. It was also suggested that this might be the result of a stronger cell-mediated immune activity in the left-side of the human body [ 14 ].…”

“…In this regard, one study reported that the onset of breast cancer among left-handed patients presents 2 years earlier compared to right-handed patients. They suggested that it was linked to higher fetal estrogen exposure in left-handed patients and advised that screening mammography should start at an earlier age in left-handed patients [ 5 , 6 ]. Ramadhani reported higher mortality from breast cancer and colorectal cancer among left-handed patients, although this was not a universal finding in other studies [ 7 , 8 ].…”