Analysis of PALB2/FANCN-associated breast cancer families

No more than approximately 30% of hereditary breast cancer has been accounted for by mutations in known genes. Most of these genes, such as BRCA1, BRCA2, TP53, CHEK2, ATM, and FANCJ/BRIP1, function in DNA repair, raising the possibility that germ line mutations in other genes that contribute to this process also predispose to breast cancer. Given its close relationship with BRCA2, PALB2 was sequenced in affected probands from 68 BRCA1/BRCA2-negative breast cancer families of Ashkenazi Jewish, French Canadian, or mixed ethnic descent. The average BRCAPRO score was 0.58. A truncating mutation (229delT) was identified in one family with a strong history of breast cancer (seven breast cancers in three female mutation carriers). This mutation and its associated breast cancers were characterized with another recently reported but unstudied mutation (2521delA) that is also associated with a strong family history of breast cancer. There was no loss of heterozygosity in tumors with either mutation. Moreover, comparative genomic hybridization analysis showed major similarities to that of BRCA2 tumors but with some notable differences, especially loss of 18q, a change that was previously unknown in BRCA2 tumors and less common in sporadic breast cancer. This study supports recent observations that PALB2 mutations are present, albeit not frequently, in breast cancer families. The apparently high penetrance noted in this study suggests that at least some PALB2 mutations are associated with a substantially increased risk for the disease.

Interobserver agreement and reproducibility in classification of invasive breast carcinoma: an NCI breast cancer family registry study

The United States National Cancer Institute Breast/Ovarian Cancer Family Registry is the largest international Registry of this type; over 37 724 individuals have been enrolled to date. One activity of this Registry is the semicentralized pathologic review of tumors from all probands. Given the semicentralized nature of the review, this study was undertaken to determine the reproducibility, source(s) of classification discrepancies and stratagems to circumvent discrepancies for histologic subtyping and grading of invasive breast cancer among the reviewing pathologists. A total of 13 pathologists reviewed 35 invasive breast cancers and classified them by primary and secondary histologic type, Nottingham grade and score. Lymph-vascular space invasion, circumscribed margins, syncytial growth and lymphocytic infiltrate were also evaluated. A training session using a separate set of slides was conducted prior to the study. General agreement, in terms of category-specific kappa's and percent agreement, and accuracy of classification relative to a reference standard were determined. Classification of histologic subtype was most consistent (and accurate) for mucinous carcinoma (kappa=1.0), followed by tubular (kappa=0.8) and lobular subtypes (kappa=0.8). Classification of medullary subtype was moderate (kappa=0.4), but additional evaluation of degree of lymphocytic infiltrate, syncytial growth and circumscribed margins identified most cases. Category-specific kappa's were moderate to good for Nottingham grade (kappa=0.5-0.7), with the greatest agreement obtained in categorizing grade I (kappa=0.7), and grade III tumors (kappa=0.7). A flexible classification strategy that employs individual and combined criteria provides good interobserver agreement for invasive breast cancers with uniform, unambiguous histology and compensates for classification discrepancies in the more histologically ambiguous or heterogeneous cancers.

HER-2/neu status and tumor morphology of invasive breast carcinomas in Ashkenazi women with known BRCA1 mutation status in the Ontario Familial Breast Cancer Registry

BACKGROUND

The prevalence of BRCA1 germline mutations is greater in the Ashkenazi Jewish population than in the general North American population. The Ontario Familial Breast Cancer Registry collects clinical and family history data in familial breast carcinoma cases, and unselected Ashkenazi breast carcinomas, and acts as a tumor tissue repository.

METHODS

Using this resource, we examined the tumor morphology, hormone receptor status, and HER-2/neu protein overexpression in Canadian Ashkenazi breast carcinoma patients whose germline BRCA1 mutation status is known.

RESULTS

Thirty-eight tumors from 32 BRCA1 carriers and 354 tumors from 334 noncarriers were analyzed. The tumors in BRCA1 mutation carriers were more likely to be high grade (P < 0.0001) and estrogen receptor negative (P < 0.004). There was an increased frequency of typical medullary carcinomas in mutation carriers when all tumors were analyzed. However, this difference did not remain statistically significant when only the first tumor diagnosed in each patient was included in the analysis. There was no difference in HER-2/neu protein overexpression between the two groups overall (P = 0.07). However, when the analysis was restricted to Grade III tumors, there were significantly fewer HER-2/neu-positive tumors in the mutation carriers versus noncarriers (3.1% vs. 21.5%, P = 0.012). No significant differences were found in the incidence of lymph node status, progesterone receptor status, lymphatic vessel invasion, degree of lymphocytic infiltration, or in the presence of ductal carcinoma in situ associated with the invasive tumors.

CONCLUSIONS

Increasing awareness of the morphologic and immunophenotypic features more commonly found in BRCA1-associated breast carcinomas may lead to a wider use of these characteristics in genetic screening programs and provide further clues to their pathogenesis.

p53-dependent regulation of heat shock protein 72

BACKGROUND

p53 is a key regulator of the cellular stress response. p53 modulates the transcription of several genes.

OBJECTIVES

To examine the influence of p53 on expression of heat shock protein 72 (HSP72).

METHODS

Two model systems were used. (i) HSP72 expression was studied by Western blot on extracts from p53-proficient or p53-deficient primary mouse keratinocytes, and (ii) archival human anogenital skin from fibroepithelial polyps, human papillomavirus (HPV) 16/18-associated lesions or squamous cell carcinomas (SCCs) was subjected to immunostaining for HSP72.

RESULTS

Basal HSP72 expression was higher in keratinocytes from p53-deficient than from p53-proficient mice. Immunostaining for HSP72 was higher in HPV 16/18 lesions and SCCs, which have reduced p53 protein.

CONCLUSIONS

p53 status may influence the basal level of HSP72.

Renal failure due to T-cell mediated lymphocytic vasculitis: an unusual complication of B-cell chronic lymphocytic leukemia

Vasculitis is an uncommon paraneoplastic syndrome, and acute renal failure is an unusual presentation of leukemia. We report a case of B-cell chronic lymphocytic leukemia that presented with acute renal failure caused by biopsy-proven lymphocytic vasculitis that subsequently was shown to be T-cell-mediated and systemic at autopsy.