Isocitrate dehydrogenase (IDH) wild-type glioblastoma (GBM) has a dismal prognosis. A better understanding of tumor evolution holds the key to developing more effective treatment. Here we study GBM's natural evolutionary trajectory by using rare multifocal samples. We sequenced 61,062 single cells from eight multifocal IDH wild-type primary GBMs and defined a natural evolution signature (NES) of the tumor. We show that the NES significantly associates with the activation of transcription factors that regulate brain development, including MYBL2 and FOSL2. Hypoxia is involved in inducing NES transition potentially via activation of the HIF1A–FOSL2 axis. High-NES tumor cells could recruit and polarize bone marrow–derived macrophages through activation of the FOSL2–ANXA1–FPR1/3 axis. These polarized macrophages can efficiently suppress T-cell activity and accelerate NES transition in tumor cells. Moreover, the polarized macrophages could upregulate CCL2 to induce tumor cell migration. Significance: GBM progression could be induced by hypoxia via the HIF1A–FOSL2 axis. Tumor-derived ANXA1 is associated with recruitment and polarization of bone marrow–derived macrophages to suppress the immunoenvironment. The polarized macrophages promote tumor cell NES transition and migration. This article is highlighted in the In This Issue feature, p. 2711

Distinction of liver metastases from hepatocellular carcinoma (HCC) may present a diagnostic challenge. Arginase-1 (Arg-1) is a marker for HCC recent

BACKGROUND Fine-needle aspiration biopsy (FNAB) of pancreatic lesions has become popular to establish a tissue diagnosis before chemotherapy and/or surgery. The diagnostic sensitivity and specificity of FNAB have improved as a result of several articles regarding cytologic criteria for pancreatic adenocarcinoma. However, false-negative and “suspicious for malignancy” rates remain relatively high, in part because of the underdiagnosis of well differentiated adenocarcinoma (WDA). Existing cytologic criteria do not specifically focus on WDA. In this study, the authors attempt to add to, redefine, and test cytologic criteria for WDA of the pancreas in FNAB specimens. METHODS The authors retrospectively reviewed the specimens of 291 consecutive computed tomography-guided FNABs of pancreatic lesions performed at the study institution between 1995 and 1999. The original cytologic diagnoses were confirmed by cell blocks (131), surgical tissue (84), or clinical follow-up. The FNAB specimens were evaluated for the presence of 10 cytologic criteria: 1) anisonucleosis, 2) nuclear membrane irregularity, 3) nuclear crowding/overlapping/three-dimensionality, 4) nuclear enlargement (if there are more than two red blood cells), 5) gap versus confluent cell spacing, 6) hyperchromasia, 7) macronucleoli, 8) mitosis, 9) chromatin clearing, and 10) necrosis. RESULTS The original cytologic diagnoses were nondiagnostic in 24 cases, benign in 27, suspicious for malignancy in 15, and malignant in 225. Among the 225 malignant lesions, 74 cases were diagnosed as WDA. Cytologic criteria 1–4 were observed in 92–99% of WDA cases, whereas criteria 5–10 were present in only 7–38% of WDA cases. Six of 15 suspicious and 4 of 27 negative cases were of low cellularity but retrospectively met the cytologic criteria 1–4 for WDA (the diagnosis was confirmed on clinical follow-up). CONCLUSIONS The diagnosis of pancreatic WDA can be made in FNAB specimens by the observance of anisonucleosis, nuclear membrane irregularity, nuclear crowding/overlapping/three-dimensionality, and nuclear enlargement. Necrosis, chromatin clearing, mitosis, macronucleoli, and hyperchromasia are of limited diagnostic significance because they are commonly absent in pancreatic WDA. Cancer (Cancer Cytopathol) 2003;99:44–50. © 2003 American Cancer Society.

Epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) is currently the standard first-line therapy for EGFR-mutated advanced non-small cell lung cancer (NSCLC). The life quality and survival of this subgroup of patients were constantly improving owing to the continuous iteration and optimization of EGFR-TKI. Osimertinib, an oral, third-generation, irreversible EGFR-TKI, was initially approved for the treatment of NSCLC patients carrying EGFR T790M mutations, and has currently become the dominant first-line targeted therapy for most EGFR mutant lung cancer. Unfortunately, resistance to osimertinib inevitably develops during the treatment and therefore limits its long-term effectiveness. For both fundamental and clinical researchers, it stands for a major challenge to reveal the mechanism, and a dire need to develop novel therapeutics to overcome the resistance. In this article, we focus on the acquired resistance to osimertinib caused by EGFR mutations which account for approximately 1/3 of all reported resistance mechanisms. We also review the proposed therapeutic strategies for each type of mutation conferring resistance to osimertinib and give an outlook to the development of the next generation EGFR inhibitors.

Context .—Differentiation of ductal adenocarcinoma of the pancreas from nonneoplastic pancreatic tissues can be challenging, especially in small biopsy and fine-needle aspiration specimens. Objective .—To investigate the utility of 26 immunohistochemical markers (CAM 5.2, CK [cytokeratin] 7, CK20, CK17, CK19, MUC1, MUC2, MUC4, MUC5AC, MUC6, p53, DPC4/SMAD4, CDX2, pVHL [von Hippel-Lindau tumor suppressor gene protein], S100P, IMP-3 [insulin-like growth factor 2 messenger RNA binding protein 3], maspin, mesothelin, claudin 4, claudin 18, annexin A8, fascin, PSCA [prostate stem cell antigen], MOC31, CEA [carcinoembryonic antigen], and CA19-9 [cancer antigen 19-9]) in the diagnosis of ductal adenocarcinoma of the pancreas. Design .—Immunohistochemical staining for these markers was performed in 60 cases of pancreatic ductal adenocarcinoma on routine and tissue microarray sections. In addition, immunohistochemical staining for maspin, S100P, IMP-3, and pVHL was performed on cell blocks from 67 pancreatic fine-needle aspiration cases, including 44 cases of pancreatic ductal adenocarcinoma. Results .—The results demonstrated that (1) more than 90% of cases of ductal adenocarcinoma were positive for maspin, S100P, and IMP-3; (2) nearly all adenocarcinoma cases were negative for pVHL, whereas nonneoplastic ducts and acini were positive for pVHL in all cases; (3) normal/reactive pancreatic ducts were frequently positive for CK7, CK19, MUC1, MUC6, CA19-9, MOC31, PSCA, mesothelin, annexin A8, claudin 4, and claudin 18; (4) normal pancreatic ducts were usually negative for IMP-3, maspin, S100P, CK17, MUC2, MUC4, and MUC5AC; (5) 60% of adenocarcinomas were negative for DPC4/SMAD4; and (6) strong background staining was frequently seen with fascin, PSCA, and annexin A8. Conclusions .—pVHL, maspin, S100P, and IMP-3 constitute the best diagnostic panel of immunomarkers for confirming the diagnosis of pancreatic ductal adenocarcinoma in both surgical and fine-needle aspiration specimens.

Human kidney injury molecule-1 (hKIM-1), a type I transmembrane glycoprotein expressed in injured renal proximal tubules, was also found in renal cell carcinoma (RCC). The current study attempts to evaluate the diagnostic utility of hKIM-1 in a large series of 480 neoplasms including defined subtypes of renal cell tumors, metastatic RCCs, and nonrenal tumors. Tissue microarray (TMA) sections containing 179 renal cell tumors (73 clear cell RCC, 30 papillary RCC, 16 chromophobe RCC, 15 oncocytoma, and 45 metastatic RCC) were included in this study. In addition, 80 cases of renal cell neoplasm and 221 nonrenal tumors in routine tissue sections were also included. Both TMA and routine sections were incubated with anti-hKIM-1 monoclonal antibody using an EnVision-HRP kit. The results demonstrated that a membranous/cytoplasmic staining pattern for hKIM-1 was observed in 54 of 73 (74%) clear cell RCCs and 28 of 30 (93%) papillary RCCs on TMA sections. Zero of 54 chromophobe RCCs and 4 of 41 (9.75%) oncocytomas were positive for hKIM-1 when combining TMA and routine sections. Similar staining results were observed in 35 of 45 (78%) metastatic RCCs. Data from cDNA microarray expression and Western blot demonstrated similar findings. Fifteen of 16 cases (93.8%) of clear cell carcinoma of the ovary demonstrated positive reactivity for hKIM-1. These data indicate that hKIM-1: (1) is a relatively sensitive and specific marker for papillary, clear cell, and metastatic RCCs, (2) can be used to distinguish clear cell from chromophobe RCC, and (3) may serve as a diagnostic marker for clear cell carcinoma of the ovary.