Prognosis of breast cancer and success of therapeutic interventions largely rely on the clinico-pathologic and biological characteristics of the tumor and vary due to the heterogeneous nature of breast cancers. The aim of this study was to determine the frequency and prognostic parameters of luminal breast cancers in our population to devise targeted and personalized therapeutic regimens tailored to the needs of the loco-regional population. A retrospective cross-sectional study including 1951 cases of primary breast cancer treated at Liaquat National Hospital Karachi was conducted during the year 2011–2016. The clinico-pathologic characteristics were observed and semiquantitative immunohistochemical analysis was performed to study the luminal subtypes A and B. The cross-tabulated statistics of the observed characteristics were performed between the two subtypes. The significance level of each characteristic was estimated utilizing the chi-square test. Luminal cancers comprised 62.7% of the total number of cases diagnosed with breast cancers in the study period. Out of these 1224 cases of luminal cancers, 845 cases (69%) were luminal B, while 379 (31%) cases were of luminal A. Luminal B cancers were significantly more common in younger age groups as compared to luminal A cancers. Comparison of the two subtypes of luminal breast cancers revealed significant differences. Luminal B cancers were associated with higher grade (26% grade III in luminal B compared to 8% in luminal A), micropapillary histology, and high frequency of nodal metastasis (54 vs. 43%). Luminal B comprised the most frequent subtype of breast cancer in our study and they were found more constantly in a younger age group. Moreover, they were associated with adverse clinico-histologic parameters like higher grade and nodal metastasis. Therefore, we suggest that, despite lack of widespread availability of molecular studies in our setup, IHC-based typing should be done in every case of breast cancer to individualize therapy.

Objectives: Ki67 is the most commonly used marker to evaluate proliferative index in breast cancer, however no cutoff values have been clearly defined for high ki67 index. Cancer management should be according to loco-regional profile; therefore, we aimed to determine ki67 index in 1951 cases of intrinsic breast cancer subtypes and its association with other prognostic parameters in our set up. Results: Triple negative breast cancers showed highest ki67 index (mean 50.9 ± 23.7%) followed by Her2neu (mean 42.6 ± 21.6%) and luminal B cancers (mean 34.9 ± 20.05%). Metaplastic and medullary breast cancers significantly showed higher ki67 index as compared to ductal carcinoma, NOS. No significant association of ki67 index was noted with any of the histologic parameters in different subtypes of breast cancer expect for tumor grade. Although, ki67 index is a valuable biomarker in breast cancer, however no independent prognostic significance of ki67 could be established in our study.

Ki67 Index in Breast Cancer: Correlation with Other Prognostic Markers and Potential in Pakistani Patients Ki67 index;breast cancer;ER;PR;HER2neu; Introduction: Breast cancer aggressiveness can be correlated with proliferation status of tumor cells, which can be ascertained with tumor grade and Ki67 indexing. However due to lack of reproducibility, the ASCO do not recommend routine use of Ki67 in determining prognosis in newly diagnosed breast cancers. We therefore aimed to determine associations of the Ki67 index with other prognostic markers like tumor size, grade, lymph node metastasis, ER, PR and HER2neu status. Methods: A total of 194 cases of newly diagnosed breast cancer were included in the study. Immunohistochemical staining for ER, PR, HER2neu and Ki67 was performed by the DAKO envision method. Associations of the Ki67 index with other prognostic factors were evaluated both as continuous and categorical variables. Results: Mean age of the patients was 51.7 years (24-90). Mean Ki67 index was 26.9% (1-90). ER, PR, HER2neu positivity was noted in 90/194 cases (46.4%), 74/194 cases (38.1%) and 110/194 cases (56.70%) respectively. Significant association was found between Ki67 and tumor grade, PR, HER2neu positivity and lymph node status, but no link was apparent with ER positivity and tumor size. There wasan inverse relation between Ki67 index and PR positivity, whereas a direct correlation was seen with HER2neu positivity. However, high Ki67 (>30%) was associated with decreased HER2neu positivity as compared to intermediate Ki67 (16-30%). The same trend was established with lymph node metastasis. Conclusion: Our study indicates that with high grade tumors, clinical utility of ki67 is greater in combination with other prognostic markers because we found that tumors with Ki67 higher than 30% have better prognostic profile compared to tumors with intermediate Ki67 level, as reflected by slightly lower frequency of lymph node metastasis and HER2neu expression. Therefore we suggest that Ki67 index should be categorized into high, intermediate and low groups when considering adjuvant chemotherapy and prognostic stratification.

Trastuzumab Deruxtecan (T-DXd) is clinically beneficial in HER2-positive and HER2-low metastatic breast cancer. However, therapeutic resistance emerges over time in most patients, with poorly defined resistance mechanisms. Through a molecular characterization of paired patient specimens before and after T-DXd treatment, we found that 49% cases had major decreases in HER2 expression at progression, and among them, 52% exhibited complete HER2 loss. Using isogenic model systems, we demonstrated that decreases in HER2 expression corresponded to reductions in T-DXd internalization and major increases in drug IC50 value for tumor growth inhibition. We further identified and validated ERBB2 mutations in the trastuzumab binding interface (V597M and P593R) that promoted T-DXd resistance. As a strategy to overcome impaired T-DXd binding and internalization, we tested low-dose combinations of T-DXd with TROP2-directed antibody–drug conjugates (ADC) and found that these could more uniformly deliver DXd payloads and thereby overcome resistance mediated by HER2 loss. Significance: The mechanisms underlying clinical T-DXd resistance have not been established. We now report on two mechanisms of resistance that converge on loss of target binding and propose combinations of distinct ADCs with shared payloads as a strategy to overcome resistance by enhancing intratumor delivery. See related commentary by O’Meara and Tarantino, p.195

Abnormal uterine bleeding (AUB) is one of the most common debilitating menstrual problems and has remained one of the most frequent indications for hysterectomy in developing countries. Approximately in 40% of hysterectomy specimens, no definite organic pathology could be established. The problem is common worldwide but causes may vary from one region to another. This study may help gynecologists in our population to improve their therapeutic strategies by promoting minimally invasive uterus sparing modalities such as endometrial ablation and hysteroscopic resection of early proliferative lesions. It was a prospective, cross-sectional study conducted at Liaquat National Hospital from 15th January 2010 till 14th July 2011 over a period of 18 months. Women who underwent dilatation and curettage for endometrial sampling with complaints of AUB were included in the study and histopathologic spectrum was determined. Polymenorrhea was the most common presenting pattern (30%, 72/241) with reproductive age women being the most susceptible (49.3%,119/241). The commonest histopathological spectrum was normal menstrual pattern (34%, 82/241) and the commonest pathology was hormonal imbalance (27%, 65/241), followed by endometrial polyp (14%, 34/241), chronic endometritis (12%, 28/241), atrophic endometrium (6%, 15/241), endometrial hyperplasia (5%, 12/241), and endometrial carcinoma (2%, 5/241). Chronic endometritis was commonly seen in reproductive age (18%, 21/119); hormonal imbalance (45%, 35/77) and endometrial hyperplasia (6.5%, 5/77) in perimenopausal age; endometrial polyp (35.5%, 16/45) and endometrial carcinoma (9%, 4/45) in postmenopausal age. Frequency of benign endometrial pathology is quite high in AUB, 236 participants (98%, 236/241). Histopathological spectrum in patients with AUB is quite variable with respect to age. The most common pattern of AUB was polymenorrhea. The most common pathology was hormonal imbalance. It is suggested that age was associated with more progressive lesions found in peri and postmenopausal age group such as endometrial hyperplasia and endometrial carcinoma. Yet endometrial polyp was the most common pathology found in postmenopausal women. Therefore, the management strategy should be individualized, as in most cases a restrictive approach is appropriate in order to avoid unnecessary hysterectomies.

Ovarian neoplasms are a heterogeneous group of tumors including surface epithelial, germ cell and sex cord stromal tumors with a subset having low malignant potential (borderline tumors). While the surgical management plan differs in different categories of tumors, preoperative diagnosis is seldom available. In these circumstances, the role of frozen section becomes invaluable. In the current study, we aimed to evaluate the accuracy of the frozen section of ovarian tumors in our setup. It was a retrospective study involving 141 cases of ovarian tumors undergoing surgical resection with frozen section evaluation from January 2009 to December 2014. After gross examination, one to five blocks were prepared on the frozen section depending upon the size of the specimen. After frozen section reporting, specimens were processed routinely for final paraffin section evaluation. Results of frozen and paraffin sections were categorized in benign, borderline, and malignant, and accuracy of frozen section was determined. Out of 141 cases, 107 were diagnosed as benign on final (paraffin) examination, while 6 were borderline and 28 were malignant. Out of 107 benign cases, 45 were non-neoplastic cystic lesions of the ovary including endometriotic, follicular, and corpus luteal cysts. The most common benign neoplastic tumor was mature cystic teratoma (20 cases) followed by mucinous cystadenoma (19 cases), serous cystadenoma (14 cases), sex cord stromal tumors (8 cases), and Brenner tumor (1 case). Among borderline cases, four cases were serous and two of mucinous neoplasms. The most common malignant neoplasm was serous carcinoma (11 cases) followed by mucinous carcinoma (6 cases). The overall accuracy of frozen section diagnosis is above 99 %. The sensitivity and specificity for benign tumors were found to be 100 and 97 %, respectively. The sensitivity and specificity for borderline tumors was 83 and 99 %, respectively, while for malignant tumors, it was 96 and 100 %, respectively. We found a high sensitivity and specificity of frozen section for the diagnosis of ovarian tumors and to determine its malignant potential. Therefore, it should always be used when the preoperative diagnosis is not definite to govern extent of surgical resection. However, under-diagnosis can occur in tumors of borderline category which can be minimized by increased sampling on the frozen section.