THINK PINK BREAST CANCER AWARENESS MONTH What are the types of breast cancer? Histologic subtypes Histology is based on the size, shape, and arrangement of breast cancer cells. More than 75% of invasive breast cancers are now histologically categorized as "no special type historically called "ductal carcinomas The most common special histologic subtype is invasive lobular carcinoma, representing about 15% of invasive breast cancers Tubular, mucinous, cribiform and papillary carcinoma are rare breast cancer subtypes that are DCIS, on the other hand, is a precursor generally associated with favorable to invasive cancer, although not prognosis. Inflammatory breast cancer all DCIS progresses. In fact, DCIS is an uncommon but aggressive type sometimes grows so slowly that even of breast cancer that is characterized without treatment it would not affect aby swelling and redness of the skin of woman's health, Long-term studies have the breast found that only 20%-53% of women with untreated DCIS are ultimately diagnosed with invasive breast cancer. DCIS patients who are premenopausal at diagnosis or who had their DCIS In Situ Historically, ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS), also known as lobular neoplasia. were considered the two main types of in situ breast cancer. However, LCIS is generally believed to be a benign condition associated w with increased breast cancer risk, but without the potential to progress to invasive cancer, so it was removed from the latest edition of the AJCC breast cancer staging system detected by palpation are at greater risk of being diagnosed with a future invasive breast cancer. During 2012- 2016, DCIS represented 16% of all breast cancer diagnoses. Invasive Most (81%) breast cancers are invasive, or inftrating, which means the abnormal cells have broken through the walls of the glands or ducts where they originated and grown into surrounding breast issue. Although breast cancer was historically referred to as a single disease, it is now considered a group of diseases, consisting of four major molecular subtypes and at least 21 distinct histological subtypes (type of issue in which the cancer originates) hat differ in risk factors, presentation response to treatment and outcomes Molecular subtypes Breast cancer molecular subtypes are determined through gene expression analysis, a costly and complicated process that is not currently standard clinical practice H However, these subtypes can be approximated using routine methods for clinical evaluation of biological markers (ER, PR, HER2 and sometimes others). Hormone receptor positive (HR+) cancers are those that test positive for ER or PR or both information about grade and proliferation (rate of cell division) is also sometimes used to assign subtype The four main molecular subtypes are described below it is worth noting that there are overlaps between categories and the clinical approximations do not perfectly correspond to the molecular breast cancer subtypes as described on the next page Luminal A (HR+/HER2-): This is the most common type of breast cancer and tends to be slower-growing and less aggressive than other subtypes. Luminal A tumors are associated with the most favorable prognosis in part because they are usually responsive to hormonal therapy Luminal B (HR+/HER2+): In addition to being HR+, this subtype was originally characterized clinically as always being positive for HER2, but more recently has been defined by being highly positive for the protein Ki67 (an indicator of a large number of actively dividing cells) and/or HER2 Luminal B breast cancers tend to be higher grade than luminal A and thus are associated with poorer outcomes. Basal-like (HR-/HER2-): These cancers are also called triple negative because they are ER-, PR- and HER2 The majority (about 75%) of triple negative breast cancers fall into the basal-like subtype defined by gene expression profiling Triple negative breast cancers have a poorer p prognosis than other subtypes, in part because treatment advances have lagged behind other molecular subtypes. These cancers occur at twice the rate in black women compared to white women in the US, and are also more common in premenopausal women and those with a BRCA1 gene mutation. HER2-enriched (HR-/HER2+); In the past, this subtype had the worst prognosis however, the widespread use of targeted therapies for HER2+ cancers has substantially improved outcomes for these patents THINK PINK BREAST CANCER AWARENESS MONTH What are the types of breast cancer ? Histologic subtypes Histology is based on the size , shape , and arrangement of breast cancer cells . More than 75 % of invasive breast cancers are now histologically categorized as " no special type historically called " ductal carcinomas The most common special histologic subtype is invasive lobular carcinoma , representing about 15 % of invasive breast cancers Tubular , mucinous , cribiform and papillary carcinoma are rare breast cancer subtypes that are DCIS , on the other hand , is a precursor generally associated with favorable to invasive cancer , although not prognosis . Inflammatory breast cancer all DCIS progresses . In fact , DCIS is an uncommon but aggressive type sometimes grows so slowly that even of breast cancer that is characterized without treatment it would not affect aby swelling and redness of the skin of woman's health , Long - term studies have the breast found that only 20 % -53 % of women with untreated DCIS are ultimately diagnosed with invasive breast cancer . DCIS patients who are premenopausal at diagnosis or who had their DCIS In Situ Historically , ductal carcinoma in situ ( DCIS ) and lobular carcinoma in situ ( LCIS ) , also known as lobular neoplasia . were considered the two main types of in situ breast cancer . However , LCIS is generally believed to be a benign condition associated w with increased breast cancer risk , but without the potential to progress to invasive cancer , so it was removed from the latest edition of the AJCC breast cancer staging system detected by palpation are at greater risk of being diagnosed with a future invasive breast cancer . During 2012 2016 , DCIS represented 16 % of all breast cancer diagnoses . Invasive Most ( 81 % ) breast cancers are invasive , or inftrating , which means the abnormal cells have broken through the walls of the glands or ducts where they originated and grown into surrounding breast issue . Although breast cancer was historically referred to as a single disease , it is now considered a group of diseases , consisting of four major molecular subtypes and at least 21 distinct histological subtypes ( type of issue in which the cancer originates ) hat differ in risk factors , presentation response to treatment and outcomes Molecular subtypes Breast cancer molecular subtypes are determined through gene expression analysis , a costly and complicated process that is not currently standard clinical practice H However , these subtypes can be approximated using routine methods for clinical evaluation of biological markers ( ER , PR , HER2 and sometimes others ) . Hormone receptor positive ( HR + ) cancers are those that test positive for ER or PR or both information about grade and proliferation ( rate of cell division ) is also sometimes used to assign subtype The four main molecular subtypes are described below it is worth noting that there are overlaps between categories and the clinical approximations do not perfectly correspond to the molecular breast cancer subtypes as described on the next page Luminal A ( HR + / HER2- ) : This is the most common type of breast cancer and tends to be slower - growing and less aggressive than other subtypes . Luminal A tumors are associated with the most favorable prognosis in part because they are usually responsive to hormonal therapy Luminal B ( HR + / HER2 + ) : In addition to being HR + , this subtype was originally characterized clinically as always being positive for HER2 , but more recently has been defined by being highly positive for the protein Ki67 ( an indicator of a large number of actively dividing cells ) and / or HER2 Luminal B breast cancers tend to be higher grade than luminal A and thus are associated with poorer outcomes . Basal - like ( HR- / HER2- ) : These cancers are also called triple negative because they are ER- , PR- and HER2 The majority ( about 75 % ) of triple negative breast cancers fall into the basal - like subtype defined by gene expression profiling Triple negative breast cancers have a poorer p prognosis than other subtypes , in part because treatment advances have lagged behind other molecular subtypes . These cancers occur at twice the rate in black women compared to white women in the US , and are also more common in premenopausal women and those with a BRCA1 gene mutation . HER2 - enriched ( HR- / HER2 + ) ; In the past , this subtype had the worst prognosis however , the widespread use of targeted therapies for HER2 + cancers has substantially improved outcomes for these patents