Lucy Webster

Molecular Grading of Ductal Carcinoma In situ of the Breast

Purpose: Increased incidence of ductal carcinoma in situ (DCIS) associated with mammographic screening for breast cancer has emphasized the challenges of managing this condition. The aim of this study was to identify informative clinical indicators of DCIS biology by molecular profiling. Experimental Design: Areas of in situ carcinoma, atypical ductal hyperplasia, and benign epithelium were microdissected from 46 invasive breast cancers. Oligonucleotide probes showing differential expression between DCIS associated with grade 1 and 3 invasive cancer were identified by microarray-based gene expression profiling. Expression at these probes was used to define a “molecular grade” subcategorization of all samples. The genomic basis of molecular grade was examined by array-based comparative genomic hybridization. Clinical course was examined in a cohort of 134 patients with DCIS treated by surgery alone. Results: DCIS samples were designated as low or high molecular grade based on expression at 173 probes. The low molecular grade subgroup included low (n = 10) and intermediate (n = 11) nuclear grade DCIS as well as all samples of atypical ductal hyperplasia (n = 4) and benign epithelium (n = 7). The high molecular grade subgroup included DCIS of intermediate (n = 7) and high (n = 19) nuclear grade. The character and degree of genomic aberration were distinct between molecular grade subgroups. A classification tree model including nuclear grade and Ki67 score accurately predicted molecular grade for 95.7% of samples. In an independent cohort, this showed a pattern of rapid disease recurrence for high molecular grade DCIS. Conclusions: Molecular profiling indicates a binary grading scheme for DCIS. This practical approach has potential to improve clinical evaluation of DCIS.

Expression of progesterone receptor A and B isoforms in low-grade endometrial stromal sarcoma

Summary:The progesterone receptor (PR) exists as two isoforms, PRA and PRB. In vitro studies have shown that these proteins are functionally distinct, suggesting that their relative expression can influence progesterone response. Low-grade endometrial stromal sarcoma (LGESS) is an uncommon tumor that usually expresses PR. In normal endometrial stroma, both PR isoforms are present with PRA predominant throughout the menstrual cycle. The relative expression of PRA and PRB in LGESS has not been previously reported. All nine cases of primary LGESS (seven uterine, two extrauterine) expressed PRB. Eight tumors also contained PRA and it was the predominant isoform in seven cases. These tumors had similar histopathologic appearances, whereas a case with approximately equal PR isoform expression showed features of sex cord or smooth muscle differentiation. An extrauterine tumor expressing only PRB had myxoid stroma. Recurrent tumor in two cases, which expressed predominantly PRA in the primary, contained reduced levels of PR consisting predominantly or entirely of PRB after prolonged interval progestin therapy. Most primary LGESSs showed PR isoform expression similar to normal endometrial stroma, consistent with the highly differentiated phenotype of this tumor. Variant differentiation or disease recurrence was accompanied by an altered PR isoform profile that could impact on hormone response.

Organophosphate-based pesticides and genetic damage implicated in bladder cancer

Organophosphate-based pesticides have been associated with pathology and chromosomal damage in humans. There are also epidemiologic links with cancer. The few screening tests for low-level occupational exposure are of doubtful sensitivity; this investigation evaluated four methods. Blood samples were studied from 10 farmers before and after occupational exposure to organophosphate-based pesticides and five unexposed controls. The standard cholinesterase test was insensitive to the exposure (P=0.815). However, a significant increase in Howell-Jolly bodies within erythrocytes was observed (P=0.001). Cytogenetic studies on routine and aphidicolin-induced blood cultures revealed that following organophosphate exposure the total number of gaps and breaks on human chromosomes was significantly increased (P=0.004 and P=0.0006, respectively). We concluded that Howell-Jolly body and fragile site analysis were sensitive indicators of nuclear damage resulting from low-level occupational exposure to organophosphate. Such nuclear damage could be implicated in carcinogenesis. The development of bladder cancer is one such example.

Histopathologic indicators of breast cancer biology: insights from population mammographic screening

Histopathologic features of breast cancer such as tumour size, grade and axillary lymph node (LN) status variably reflect tumour biology and time. Recent evidence suggests that the biological character of breast cancer is established at an early stage and has a major impact on clinical course. The aim of this study was to distinguish the impact of biology on breast cancer histopathology by comparing features of breast cancers diagnosed following population mammographic screening with prevalent vs incident detection and screening interval. Central histopathology review data from 1147 cases of ductal in situ and/or invasive breast cancer were examined. Size, grade and LN status of invasive cancers were positively correlated (P<0.001). Prevalent invasive cancers were larger (P<0.001) and more likely to be LN positive (P=0.02) than incident cases, but grade was not associated with screening episode (P=0.7). Screening interval for incident cancers was positively associated with invasive cancer size (P=0.05) and LN status (P=0.002) but not grade (P=0.1). Together, these data indicate that biology and time both impact on size and LN status of invasive breast cancer, but grade reflects biology alone. In view of the clinical importance of breast cancer biology, grade as its most direct indicator assumes particular significance.

Fragile sites and bladder cancer

Continued reports of associations between environmentally induced chromosomal fragile sites and cancer prompted us to undertake a review of current literature to examine whether there might be a relationship between fragile sites and chromosomal alterations reported for bladder cancer. It was found that more than half (56%; odds ratio [OR] = 4.70) of chromosomal rearrangements reported for bladder cancer were located at 77 (65%) of the 118 recognized fragile sites (OR = 6.88). Furthermore, 55% of the fragile sites implicated coincided with one or more genes that have been associated with human cancer (such as oncogenes, tumor suppressor, relonc, transloc, disorder, apoptotic, and angiogenic genes). The most common fragile sites involved were FRA1D, FRA1F, FRA8C, FRA9D, FRA9E, and FRA11C. This correlation suggests that there may be profiles of genetic damage via fragile site expression that lead to the development of at least a proportion of bladder cancers.

Poor-Prognosis Estrogen Receptor–Positive Breast Cancer Identified by Histopathologic Subclassification

Purpose: Identification of biologically and clinically distinct breast cancer subtypes could improve prognostic assessment of primary tumors. The characteristics of “molecular” breast cancer subtypes suggest that routinely assessed histopathologic features in combination with limited biomarkers may provide an informative classification for routine use. Experimental Design: Hierarchical cluster analysis based on components of histopathologic grade (tubule formation, nuclear pleomorphism, and mitotic score), expression of ER, cytokeratin 5/6, and HER2 amplification identified four breast cancer subgroups in a cohort of 270 cases. Cluster subgroup membership was compared with observed and Adjuvant! Online predicted 10-year survival. Survival characteristics were confirmed in an independent cohort of 300 cases assigned to cluster subgroups using a decision tree model. Results: Four distinct breast cancer cluster subgroups (A-D) were identified that were analogous to molecular tumor types and showed a significant association with survival in both the original and validation cohorts (P < 0.001). There was a striking difference between survival for patients in cluster subgroups A and B with ER+ breast cancer (P < 0.001). Outcome for all tumor types was well estimated by Adjuvant! Online, with the exception of cluster B ER+ cancers where Adjuvant! Online was too optimistic. Conclusions: Breast cancer subclassification based on readily accessible pathologic features could improve prognostic assessment of ER+ breast cancer.

Immunohistochemical expression and prognostic significance of oestrogen receptor-alpha, oestrogen receptor-beta, and progesterone receptor in stage 1 adult-type granulosa cell tumour of the ovary

Aims: To assess oestrogen receptor (ER)&agr;, ER&bgr;, and progesterone receptor (PR) expression in stage I ovarian adult-type granulosa cell tumours (AGCTs) and correlate the findings with clinical outcome. Methods: ER&agr;, ER&bgr; and PR immunohistochemistry was performed on 56 primary, stage I AGCTs. Twelve cases (21%) recurred and hormone receptor staining was compared in the corresponding primary and metastatic tumours. Results: All primary AGCTs expressed ER&bgr; and PR, usually with strong and diffuse staining, whereas only 20% of tumours were focally ER&agr; positive. There was no correlation between ER&agr; or PR expression and outcome. However, primary AGCTs with low ER&bgr; expression had a significantly higher risk of recurrence. In contrast, all metastatic tumours exhibited strong ER&bgr; staining. No relationship between ER staining and tumour morphology was identified but there was more consistent PR expression in cells at the tumour–stromal interface. Conclusions: Primary AGCTs typically show an ER&agr; negative and ER&bgr;/PR positive immunophenotype. Low ER&bgr; expression is an adverse prognostic factor in primary AGCT but metastatic tumours often show up-regulation of ER&bgr;. Local microenvironmental factors may influence PR expression. Hormone receptor expression in AGCT may become increasingly relevant due to developments in selective therapy.

Cancer Screening among Immigrants Living in Urban and Regional Australia: Results from the 45 and Up Study

Over 25% of the Australian population are immigrants, and are less active participants in cancer screening programmes. Most immigrants live in urban areas of Australia, but a significant proportion (~20%), live in regional areas. This study explored differences in cancer screening participation by place of birth and residence. Self-reported use of mammogram, faecal occult blood test (FOBT), and/or prostate specific antigen (PSA) tests was obtained from 48,642 immigrants and 141,275 Australian-born participants aged 50 years or older in the 45 and Up Study (New South Wales, Australia 2006–2010). Poisson regression was used to estimate relative risks of test use, adjusting for key socio-demographic characteristics. Overall, immigrants from Asia and Europe were less likely to have had any of the tests in the previous two years than Australian-born participants. Regional Australian-born participants were more likely to have had any of the tests than those living in urban areas. Regional immigrant participants were more likely to have had an FOBT or PSA test than those living in urban areas, but there were no differences in mammograms. This report identifies key immigrant groups in urban and regional areas that policymakers and healthcare providers should target with culturally appropriate information to promote cancer screening

Prohibitin expression is associated with high grade breast cancer but is not a driver of amplification at 17q21.33

Aims: In a study of ductal carcinoma in situ of the breast, we identified five genes at chromosome 17q21.33 that were over-expressed in high grade cases, and showed a correlation between expression and gene copy number. The aim of this study was to investigate potential drivers of genomic amplification at 17q21.33. Methods: Analysis of high resolution comparative genomic hybridisation and published data specified a minimum region of amplification at 17q21.33. Prohibitin (PHB) expression was examined by immunohistochemistry in 285 invasive breast cancers. Gene copy number was examined by fluorescence in situ hybridisation. Results: The minimum region of amplification at 17q21.33 included ten genes with PHB selected as a candidate driver. Increased PHB expression was associated with higher grade breast cancer and poorer survival. Amplification of PHB was detected in 13 of 235 cases (5.5%) but was not associated with PHB expression. PHB amplification was most common in the ERBB2+ breast cancer subtype, although high expression was most prevalent in basal-like and luminal B cancers. Conclusions: Amplification at 17q21.33 is a recurrent feature of breast cancer that forms part of a ‘firestorm’ pattern of genomic aberration. PHB is not a driver of amplification, however PHB may contribute to high grade breast cancer.