Isolated tumor cells in breast cancer sentinel lymph nodes: displacement or metastases? An immunohistochemical study

Structural Defect-Enabled Magnetic Neutrality Nanoprobes for Ultra-High-Field Magnetic Resonance Imaging of Isolated Tumor Cells in Vivo

The identification of metastasis "seeds," isolated tumor cells (ITCs), is of paramount importance for the prognosis and tailored treatment of metastatic diseases. The conventional approach to clinical ITCs diagnosis through invasive biopsies is encumbered by the inherent risks of overdiagnosis and overtreatment. This underscores the pressing need for noninvasive ITCs detection methods that provide histopathological-level insights. Recent advancements in ultra-high-field (UHF) magnetic resonance imaging (MRI) have ignited hope for the revelation of minute lesions, including the elusive ITCs. Nevertheless, currently available MRI contrast agents are susceptible to magnetization-induced strong T2-decaying effects under UHF conditions, which compromises T1 MRI capability and further impedes the precise imaging of small lesions. Herein, this study reports a structural defect-enabled magnetic neutrality nanoprobe (MNN) distinguished by its paramagnetic properties featuring an exceptionally low magnetic susceptibility through atomic modulation, rendering it almost nonmagnetic. This unique characteristic effectively mitigates T2-decaying effect while concurrently enhancing UHF T1 contrast. Under 9 T MRI, the MNN demonstrates an unprecedentedly low r2/r1 value (≈1.06), enabling noninvasive visualization of ITCs with an exceptional detection threshold of ≈0.16 mm. These high-performance MNNs unveil the domain of hitherto undetectable minute lesions, representing a significant advancement in UHF-MRI for diagnostic purposes and fostering comprehensive metastasis research.

Diagnostic Challenges Caused by Endoscopic Biopsy of Colonic Polyps: A Systematic Evaluation of Epithelial Misplacement With Review of Problematic Polyps From the Bowel Cancer Screening Program, United Kingdom

Endoscopic mucosal biopsy may misplace mucosal elements into the submucosa of colonic adenomas, mimicking invasive adenocarcinoma. Biopsy-related misplacement can be more challenging to recognize than typical misplaced epithelium (pseudoinvasion) in pedunculated polyps. We compared the features of 16 polyps with biopsy-related misplaced epithelium with those of 10 adenomas with pseudoinvasion and 10 adenomas with invasive adenocarcinoma and performed Ki67 and p53 immunostaining on all cases. Features of misplaced epithelium in polyps referred to the Bowel Cancer Screening Program Expert Board in the United Kingdom were also evaluated for the same morphologic features. Biopsy-related epithelial misplacement occurred in adenomas throughout the colon and often appeared infiltrative (69%), including epithelial cells singly dispersed within reactive fibroinflammatory stroma or granulation tissue (44%). Misplaced epithelium displayed only low-grade cytologic features and was associated with extruded mucin (75%), tattoo pigment (63%), and misplaced normal glands (38%); scant lamina propria and muscularis mucosae were often present (88% and 44%, respectively). Cases referred to the Bowel Cancer Screening Program Expert Board also contained infiltrative-appearing misplaced epithelium (91%) that was cytologically low grade (72%), contained nondysplastic glands (11%), and showed other signs of injury. In contrast, misplaced epithelium in pedunculated polyps always had a lobular contour with a rim of lamina propria, hemorrhage, and/or hemosiderin. Invasive carcinomas showed malignant cytology and desmoplasia; most (70%) lacked features of trauma. Ki67 and p53 staining was patchy and weak in the misplaced epithelium, whereas invasive carcinomas showed increased staining for one or both markers. Pathologists should be aware that endoscopically manipulated adenomas may contain misplaced epithelium that simulates malignancy.

False-positive and false-negative sentinel node findings in 473 breast cancers

We reviewed lymph node samples from 473 consecutive breast cancer cases with either negative sentinel nodes or isolated tumor cells to evaluate the rate of false-positive sentinel node findings. Nuclear morphometry was applied to compare nuclear atypia between the primary tumor and metastases classified as isolated tumor cells by size. In addition, the role of the diagnostic preoperative biopsy method, either core needle biopsy or fine needle aspiration cytology, on the prevalence of isolated tumor cells was investigated. In addition, we studied the expression of metastasis-associated protein 1 in the primary tumor and corresponding metastases in 95 cases, including 52 isolated tumor cell cases, to distinguish a true metastasis from a benign epithelial displacement. Our review revealed 4 false positives and 7 false negatives from 473 sentinel node cases. In addition, 5 true-positive cases were upstaged from isolated tumor cells to micrometastases. No association was found between the preoperative biopsy method and the sentinel node status (P=.859). There was no difference in nuclear atypia, when the cells in isolated tumor cells and primary tumor were compared. Therefore, small metastases do not represent benign epithelial displacement. Isolated tumor cell findings did not correlate with preoperative biopsy methods. The metastasis-associated protein 1 staining score sum was lower in the metastases than in the primary tumor in 72% of cases, including all sizes of metastases. These data suggest that metastasis-associated protein 1 staining is not ideal for investigating the possible malignant nature of smaller metastases because of the relatively low concordance between the primary tumor and metastases, even macrometastases.

Prognostic impact of isolated tumor cells in breast cancer axillary nodes: single tumor cell(s) versus tumor cell cluster(s) and microanatomic location

In breast cancer, it has been shown that pN0(i+) and pN1mi have a comparable negative impact on disease-free survival, compared with pN0. However, pN0(i+) is considered to be a heterogeneous group. We determined the effect of metastatic size and microanatomic location within the pN0(i+) group on breast cancer recurrence. We included all Dutch breast cancer patients diagnosed in 1998-2005 with favorable primary tumor characteristics and a final nodal status of pN0(i+). For this analysis, only patients without adjuvant systemic therapy were eligible (n = 513). Presence of single tumor cells versus cell clusters, metastatic size and microanatomic location were recorded. Primary endpoint was disease-free survival. Analyses were adjusted for age at diagnosis, tumor size, tumor grade, axillary treatment and hormone receptor status. The 5-year disease-free survival of patients with single tumor cell(s) (n = 93) was 78.6% and with tumor cell cluster(s) (n = 404) 77.1%. The hazard ratio for disease events was 1.05 (95% CI 0.63-1.76) for cell cluster(s) compared with single cell(s). In a Cox regression model, doubling of metastatic tumor size corresponded to a hazard ratio of 1.21 (95% CI 1.02-1.43). The adjusted hazard ratio was 0.90 (95% CI 0.54-1.50) for parenchymal (n = 112) versus sinusoidal location (n = 395). Single tumor cells bear similar prognostic information as small tumor cell clusters, even though results do suggest that within the pN0(i+) group, increasing size of nodal involvement is associated with reduced survival. Microanatomic location does not seem to have prognostic relevance.