Background and Objectives: Calcium (Ca2+) signaling is critical for the normal functioning of various cellular activities. However, abnormal changes in cellular Ca2+ can contribute to pathological conditions, including various types of cancer. The maintenance of intracellular Ca2+ levels is achieved through tightly regulated processes that help maintain Ca2+ homeostasis. Several types of regulatory proteins are involved in controlling intracellular Ca2+ levels, including the sarco/endoplasmic reticulum (SR/ER) Ca2+ ATPase pump (SERCA), which maintains Ca2+ levels released from the SR/ER. In total, three ATPase SR/ER Ca2+-transporting (ATP2A) 1-3 genes exist, which encode for several isoforms whose expression profiles are tissue-specific. Recently, it has become clear that abnormal SERCA expression and activity are associated with various types of cancer, including breast cancer. Breast carcinomas represent 40% of all cancer types that affect women, with a wide variety of pathological and clinical conditions. Materials and methods: Using cBioPortal breast cancer patient data, Kaplan–Meier plots demonstrated that high ATP2A1 and ATP2A3 expression was associated with reduced patient survival. Results: The present study found significantly different SERCA specific-type expressions in a series of breast cancer cell lines. Moreover, bioinformatics analysis indicated that ATP2A1 and ATP2A3 expression was highly altered in patients with breast cancer. Conclusion: Overall, the present data suggest that SERCA gene-specific expressioncan possibly be considered as a crucial target for the control of breast cancer development and progression.