Squamous cell carcinoma of the breast, are there two entities with distinct prognosis? A series of 39 patients

Case report: Successful treatment of a rare HER2-positive advanced breast squamous cell carcinoma

Background: Breast squamous cell carcinoma (SCC) is an uncommon and highly aggressive variant of metaplastic breast cancer. Despite its rarity, there is currently no consensus on treatment guidelines for this specific subtype. Previous studies have demonstrated that chemotherapy alone has limited efficacy in treating breast SCC. However, the potential for targeted therapy in combination with chemotherapy holds promise for future treatment options. Case presentation: In this case report, we present a patient with advanced HER2-positive breast SCC, exhibiting a prominent breast mass, localized ulcers, and metastases in the lungs and brain. Our treatment approach involved the administration of HER2-targeted drugs in conjunction with paclitaxel, resulting in a sustained control of tumor growth. Conclusion: This case represents a rare occurrence of HER2-positive breast SCC, with limited available data on the efficacy of previous HER2-targeted drugs in treating such patients. Our study presents the first application of HER2-targeted drugs in this particular case, offering novel therapeutic insights for future considerations. Additionally, it is imperative to conduct further investigations to assess the feasibility of treatment options in a larger cohort of patients.

The mixed subtype has a worse prognosis than other histological subtypes: a retrospective analysis of 217 patients with metaplastic breast cancer

OBJECTIVE

Metaplastic breast cancer (MpBC) is an aggressive subtype of all breast cancer. We aimed to investigate the clinicopathological features, treatments and prognoses of MpBC patients.

METHODS

We collected the data from MpBC patients diagnosed at Tianjin Medical University Cancer Hospital from 2010 to 2017. Kaplan Meier curves and Cox regression model were used to evaluating clinical outcomes and prognostic factors. After removing baseline differences by propensity score matching (PSM), we analyzed the prognosis between MpBC patients and invasive ductal carcinomas of no special type (IDC-NST) patients.

RESULTS

A total of 217 MpBC patients were subsumed. Of all histological subtypes, 45.1% were mixed subtypes, followed by with mesenchymal differentiation (27.2%), pure squamous (15.2%) and pure spindle (12.4%) subtypes. 69.6% of MpBC were triple-negative, 25.3% and 6.5% were HR-positive and HER2-positive. MpBC patients had worse survival compared to IDC-NST patients, with 5-year RFS of 73.8 and 83.6% (HR = 1.177 95%CI (1.171-2.676) P = 0.0068), and 5-year BCSS of 79.0% and 89.7% (HR = 2.187 95%CI (1.357-3.523) P = 0.0013). In the multivariate COX model, AJCC stage, mixed subtype and chemotherapy were independent prognostic factors. Mixed MpBC is more aggressive than pure and with heterologous mesenchymal differentiation subtypes. And whether squamous or spindle MpBC, mixed forms have shorter outcomes than pure forms.

CONCLUSIONS

MpBCs are associated with poorer prognoses than IDC-NSTs. They are heterogeneous with different clinicopathological features and clinical outcomes between histological subtypes. Pure and with heterologous mesenchymal differentiation subtypes have more survival benefits than the mixed subtype.

Preoperative MRI of breast squamous cell carcinoma: diagnostic value of distinguishing between two subtypes

AIM

To retrospectively analyse the clinical and MRI data of primary squamous cell carcinoma (SCC), particularly pure squamous cell carcinoma (PSCC) and mixed squamous cell carcinoma (MSCC).

MATERIALS AND METHODS

The MRI data and clinicopathological characteristics of 20 patients with histopathologically confirmed SCC of the breast, including eight PSCC patients and 12 MSCC patients, from multiple centres between January 2013 and December 2020 were analysed retrospectively.

RESULTS

Nine of 12 patients in the MSCC group showed hyperintensity on T1-weighted imaging (WI), while this feature was not observed in the PSCC group (p=0.001). Most of the PSCC group showed rim enhancement, whereas most of the MSCC group showed heterogeneous enhancement (p=0.007). In addition, there was no significant difference in the thickness of the rim enhancement and the percentage of necrotic components in the tumours between the two types of SCCs of the breast (p=0.545 and p=0.662, respectively). Four patients (4/12) in the MSCC group had sentinel lymph node metastasis, while only one patient (1/8) in the PSCC group showed lymph node metastasis (p=0.603). Metastatic disease occurred in 25% of patients with PSCC and in approximately 41.7% of patients with MSCC.

CONCLUSION

The signal on T1WI and internal enhancement characteristics were the key features for differentiating PSCC and MSCC. Therefore, MRI phenotypes may provide additional information for the pathological classification of breast SCC.

Prognosis of Subcutaneous Mastectomy for Special Types of Breast Cancer

Background and objectives: In the treatment of the special type of breast cancer (STBC), the choice of chemotherapeutic agents is often based on the characteristic features of the histological type. On the other hand, the surgical strategy is usually determined by the tumor size and presence of lymph node metastasis, and the indication for immediate reconstruction is rarely discussed based on the histological type. The prognoses of STBC and invasive ductal carcinoma of the breast (IDC) patients who underwent subcutaneous mastectomy (SCM) with immediate reconstruction at our institution were compared. Materials and Methods: A total of 254 patients with SCM with immediate reconstruction from 1998 to 2018 were included; their tumor diameter or induration was less than 25 mm, and it was not in close proximity to the skin. Preoperative chemotherapy and non-invasive cancer cases were excluded. Results: The number of patients was 166 for skin-sparing mastectomy (SSM) and 88 for nipple-sparing mastectomy (NSM). The reconstructive techniques were deep inferior epigastric artery perforator flap (DIEP) reconstruction in 43 cases, latissimus dorsi flap reconstruction (LDflap) in 63 cases, tissue expander (TE) in 117 cases, and transverse rectus abdominis myocutaneous flap/vertical rectus abdominis myocutaneous flap (TRAM/VRAM) reconstruction in 31 cases. The histological types of breast cancer were 211 IDC and 43 STBC; 17 were mucinous carcinoma (MUC), 17 were invasive lobular carcinoma (ILC), 6 were apocrine carcinoma, 1 was tubular carcinoma, and 2 were invasive micropapillary carcinoma. There was no difference in local recurrence or disease-free survival (LRFS, DFS) between IDC and STBC, and overall survival (OS) was significantly longer in STBC. OS was better in the STBC group because SCM with immediate reconstruction was performed for STBC, which is a histological type with a relatively good prognosis. Highly malignant histological types, such as squamous cell carcinoma or metaplastic carcinoma, were totally absent in this study. Conclusions: The indications for SCM with immediate reconstruction for relatively common STBCs such as MUC and ILC can be the same as for IDC.

Lumpectomy Combined with Adjuvant Radiotherapy Could Be a Treatment Option for Primary Squamous Cell Carcinoma of the Breast

Background

To investigate the outcomes of primary squamous cell carcinoma (PSCC) of the breast undergoing radical surgery with or without adjuvant radiotherapy (RT).

Materials and Methods

A population cohort with histologically diagnosed PSCC of the breast was identified from the SEER database. The Kaplan-Meier method and Cox-regression proportional hazards model was used to assess the impact of surgical types with or without adjuvant RT on the cause-specific survival (CSS) and overall survival (OS). A retrospective analysis of PSCC between Jan 2010 and Dec 2018 from our institute was performed.

Results

A total of 515 patients with PSCC of the breast were included, 254 patients treated with mastectomy (MAST) alone, 78 with MAST + RT, 87 with lumpectomy (LUMP) alone, and 96 with LUMP + RT. The median follow-up time was 118 months (range: 0-379 months). In the multivariate Cox analyses, LUMP + adjuvant RT was an independent prognostic factor for CSS (p = 0.028) and OS (p = 0.048). Patients treated with LUMP + RT had better survival rates than patients who underwent lumpectomy (CSS, p = 0.034; OS, p = 0.0004), MAST alone (CSS, p = 0.0001; OS, p < 0.0001), and MAST + RT (CSS, p = 0.0001; OS, p = 0.0078), while postmastectomy RT did not significantly improve OS (p = 0.062) and CSS (p = 0.67) when compared to MAST alone. In addition, a total of 28 patients with PSCC of the breast were identified from our institute. All of these patients presented with estrogen receptor-negative type, and three of them had HER-2-positive PSCC; the median tumor size was 3 cm (range: 0.5-15 cm). Eight patients were treated with LUMP + adjuvant RT, thirteen with MAST, and seven with MAST + RT. Until the last follow-up of Sep 2021, 26 patients with PSCC were still alive and free of breast cancer, excepting that one patient treated with MAST and one patient with MAST + RT died from breast cancer.

Conclusion

PSCC of the breast after radical surgery has a poor prognosis. Adjuvant RT after LUMP significantly improves survival of patients with PSCC of the breast. Further studies are still needed to investigate the role of adjuvant RT in PSCC of the breast after mastectomy.

Bidirectional Regulatory Cross-Talk between Cell Context and Genomic Aberrations Shapes Breast Tumorigenesis

Breast cancers are classified into five intrinsic subtypes and 10 integrative clusters based on gene expression patterns and genomic aberrations, respectively. Although the cell-of-origin, adaptive plasticity, and genomic aberrations shape dynamic transcriptomic landscape during cancer progression, how interplay between these three core elements governs obligatory steps for a productive cancer progression is unknown. Here, we used genetic ancestry-mapped immortalized breast epithelial cell lines generated from breast biopsies of healthy women that share gene expression profiles of luminal A, normal-like, and basal-like intrinsic subtypes of breast cancers and breast cancer relevant oncogenes to develop breast cancer progression model. Using flow cytometry, mammosphere growth, signaling pathway, DNA damage response, and in vivo tumorigenicity assays, we provide evidence that establishes cell context-dependent effects of oncogenes in conferring plasticity, self-renewal/differentiation, intratumor heterogeneity, and metastatic properties. In contrast, oncogenic aberrations, independent of cell context, shaped response to DNA damage-inducing agents. Collectively, this study reveals how the same set of genomic aberration can have distinct effects on tumor characteristics based on cell-of-origin of tumor and highlights the need to utilize multiple "normal" epithelial cell types to decipher oncogenic properties of a gene of interest. In addition, by creating multiple isogenic cell lines ranging from primary cells to metastatic variants, we provide resources to elucidate cell-intrinsic properties and cell-oncogene interactions at various stages of cancer progression. IMPLICATIONS: Our findings demonstrate that how an interplay between the normal cell type that encountered genomic aberrations and type of genomic aberration influences heterogeneity, self-renewal/differentiation, and tumor properties including propensity for metastasis.

Epithelial Mesenchymal Transition and Immune Response in Metaplastic Breast Carcinoma

Metaplastic breast carcinoma (MBC) is a heterogeneous group of infrequent triple negative (TN) invasive carcinomas with poor prognosis. MBCs have a different clinical behavior from other types of triple negative breast cancer (TNBC), being more resistant to standard chemotherapy. MBCs are an example of tumors with activation of epithelial–mesenchymal transition (EMT). The mechanisms involved in EMT could be responsible for the increase in the infiltrative and metastatic capacity of MBCs and resistance to treatments. In addition, a relationship between EMT and the immune response has been seen in these tumors. In this sense, MBC differ from other TN tumors showing a lower number of tumor-infiltrating lymphocytes (TILS) and a higher percentage of tumor cells expressing programmed death-ligand 1 (PD-L1). A better understanding of the relationship between the immune system and EMT could provide new therapeutic approaches in MBC.

Molecular Features of Metaplastic Breast Carcinoma: An Infrequent Subtype of Triple Negative Breast Carcinoma

Metaplastic breast carcinoma (MBC) is a heterogeneous group of infrequent invasive carcinomas that display differentiation of the neoplastic epithelium towards squamous cells and/or mesenchymal-type elements. Most MBC have a triple negative phenotype and poor prognosis. Thus, MBC have worse survival rates than other invasive breast carcinomas, including other triple negative breast carcinomas (TNBC). In this study, we reviewed the molecular features of MBC, pointing out the differences among subtypes. The most frequently mutated genes in MBC were TP53 and PIK3CA. Additionally, mutations in the other genes of the PI3K/AKT pathway indicated its importance in the pathogenesis of MBC. Regarding copy number variations (CNVs), MYC was the most frequently amplified gene, and the most frequent gene loss affected the CDKN2A/CDKN2B locus. Furthermore, the pattern of mutations and CNVs of MBC differed from those reported in other TNBC. However, the molecular profile of MBC was not homogeneous among histological subtypes, being the alterations in the PI3K pathway most frequent in spindle cell carcinomas. Transcriptomic studies have demonstrated an epithelial to mesenchymal program activation and the enrichment of stemness genes in most MBC. In addition, current studies are attempting to define the immune microenvironment of these tumors. In conclusion, due to specific molecular features, MBC have a different clinical behavior from other types of TNBC, being more resistant to standard chemotherapy. For this reason, new therapeutic approaches based on tumor molecular characteristics are needed to treat MBC.