Proficiency testing of diagnosis in histopathology and immunohistochemistry of breast pathology in China: results from a pilot work of National Single Disease Quality Control Program for breast cancer.

AIM: Pathologists are currently supposed to be aware of both domestic and international guidelines for breast cancer diagnosis, but it is unclear how successfully these guidelines have been integrated into routine clinical practice in China. Thus, this national proficiency testing (PT) scheme for breast pathology was set up to conduct a baseline assessment of the diagnostic capability of pathologists in China. METHODS: This national PT plan is designed and implemented according to the "Conformity assessment-General requirements for proficiency testing" (GB/T27043-2012/ISO/IEC 17043:2010). Five cases of breast cancer with six key items, including histologic type, grade, ER, PR, HER2, and Ki67, were selected for testing among 96 participants. The final PT results were published on the website of the National Quality Control Center for Cancer ( http://117.133.40.88:3927/cn/col22/362 ). RESULTS: Our study demonstrated that the median PT score was 89.5 (54-100). Two institutions with scores < 67 were deemed unacceptable. The accuracy of histologic type, ER, PR, HER2, and Ki67 was satisfactory (all > 86%). However, the histologic grade showed low accuracy (74.0%). The unacceptable results mainly included incorrect evaluation of histologic grade (36.7%), inaccurate evaluation of ER/PR/HER2/Ki67 (28.2%), incorrect identification of C-AD as IBC-NST (15.7%), inappropriate use of 1+/2+/3+ rather than staining percentage for ER/PR (6.1%), misclassification of ER/PR < 1% weak expression as positive staining (1.4%), and no evaluation of histologic grade in ILC, MC, and IMC (5.8%). CONCLUSIONS: our nationwide PT program exhibited a satisfactory baseline assessment of the diagnostic capability of pathologists in China. More importantly, we identify some areas for further improvement.

Immunohistochemical detection of the BRAF V600E mutation in melanoma patients with monoclonal antibody VE1.

A novel mutation-specific monoclonal antibody VE1 was generated to detect BRAF V600E mutation with immunohistochemistry. This study aims to investigate the sensitivity and specificity of immunohistochemistry compared with conventional Sanger sequencing and to evaluate whether IHC would become the routine screening method of BRAF V600E mutation. A total of 84 cases of melanoma lesion specimens were selected to make the tissue microarray and to perform IHC with VE1 antibody. Simultaneously Sanger sequencing was applied to test and verify. VE1 has a high specificity (100%) and sensitivity (72.2%), and the concordance between the two techniques is excellent (93.8% cases coherent and kappa = 0.801). As a rapid, cost-effective method, IHC may become the routine diagnostic means for the detection of BRAF V600E mutation of malignant melanomas in the near future, and the recommended detection process is initial immunohistochemical staining for positive cases, followed by molecular techniques for negative or ambiguous cases.

In Situ Polymerized Zwitterionic Copolymer Ionic Gel Electrolytes with High Performance for Lithium-Ion Batteries.

Gel electrolytes are a promising research direction due to their high safety. However, its poor room temperature conductivity along with complex preparation process hinder its practical application. In this article, a type of zwitterionic gel electrolyte is prepared by in situ polymerization. The introduction of charged but nonmigrating zwitterionic copolymer in the polymer chain is beneficial to the dissociation of the lithium salt, improving the ion transport of the electrolyte on this account. At room temperature, the conductivity of lithium ion reaches 9.1 × 10-4 S cm-1, which contributes to achieve excellent electrochemical performance at high rates. The assembled Li|LiFePO4 cell also shows a capacity retention rate of 90.5% after 150 cycles at 0.5 C at room temperature as well as remarkable cycle stability at 1 C. These offer a novel tactic for the efficient and safe commercial application of lithium-ion batteries.

Weak Solvation Chemistry in Fluorinated Nonflammable Electrolytes Achieves Stable Cycling in High-Voltage Lithium Metal Batteries.

High-voltage (>4.35 V) lithium nickel-cobalt-manganese batteries are star candidates due to their higher energy density for next-generation power batteries. This poses higher demands for electrolyte design, including compatibility with lithium metals, stability on high-voltage cathodes, speedy interfacial ion transport kinetics, and appropriate concentration. However, electrolytes at the current level of research struggle to balance these demands. Here, we took advantage of the reduced affinity with Li+ and enhanced oxidative stability of three fluorinated linear carbonates to design a series of weakly solvating electrolytes (WSEs) at a low salt concentration of 1 M, which contain abundant ionic cluster structures, leading to the optimization of interfacial chemistry. As a result, WSEs can support the stable cycling of 4.6 V high-voltage Li||NCM811 cells for 300 cycles with a capacity retention of nearly 80%. Moreover, benefiting from the lower desolvation energy of Li+, WSEs achieve superior cycling stability and low polarization under -20 °C. Our work extends the application of WSEs for high-voltage LMBs, providing a promising solution in electrolytes for high-specific-energy lithium batteries.

Improving Fast-Charging Capability of High-Voltage Spinel LiNi0.5 Mn1.5 O4 Cathode under Long-Term Cyclability through Co-Doping Strategy.

Co-free spinel LiNi0.5 Mn1.5 O4 (LNMO) is emerging as a promising contender for designing next generation high-energy-density and fast-charging Li-ion batteries, due to its high operating voltage and good Li+ diffusion rate. However, further improvement of the Li+ diffusion ability and simultaneous resolution of Mn dissolution still pose significant challenges for their practical application. To tackle these challenges, a simple co-doping strategy is proposed. Compared to Pure-LNMO, the extended lattice in resulting LNMO-SbF sample provides wider Li+ migration channels, ensuring both enhanced Li+ transport kinetics, and lower energy barrier. Moreover, Sb creating structural pillar and stronger TM─F bond together provides a stabilized spinel structure, which stems from the suppression of detrimental irreversible phase transformation during cycling related to Mn dissolution. Benefiting from the synergistic effect, the LNMO-SbF material exhibits a superior reversible capacity (111.4 mAh g-1 at 5C, and 70.2 mAh g-1 after 450 cycles at 10C) and excellent long-term cycling stability at high current density (69.4% capacity retention at 5C after 1000 cycles). Furthermore, the LNMO-SbF//graphite full cell delivers an exceptional retention rate of 96.9% after 300 cycles, and provides a high energy density at 3C even with a high loading. This work provides valuable insight into the design of fast-charging cathode materials for future high energy density lithium-ion batteries.

Prognostic value of microsatellite instability in sporadic locally advanced rectal cancer following neoadjuvant radiotherapy.

AIMS: This study was conducted to investigate the clinicopathological significance and prognostic value of microsatellite instability (MSI) in locally advanced rectal cancer (LARC) following neoadjuvant radiotherapy. METHODS AND RESULTS: A total of 316 consecutive patients with LARC who underwent neoadjuvant radiotherapy and curative surgery were included retrospectively. Microsatellite instability in pretreatment biopsy tissue was assessed using the pentaplex panel of mononucleotides. Twenty-five tumours (7.9%) were assessed as high-frequency MSI (MSI-H) and 291 were low-frequency MSI (MSI-L; n = 42) or microsatellite stable (MSS; n = 249). There were no significant differences in terms of gender, age, tumour location or pretreatment serum carcinoembryonic antigen between the MSI-H and MSI-L + MSS groups. Microsatellite instability was not associated statistically with pathological stage, radiation-induced tumour regression or downstaging. No significant difference was found in disease-free survival (DFS) between the two groups but, within the subgroup of ypN0 stage, patients with MSI-H tumours presented a significantly improved DFS compared with those with MSI-L or MSS tumours (100% versus 79.8%, P < 0.05), whereas no DFS improvement was observed for patients with MSI-H tumours in the ypN + subgroup. CONCLUSIONS: Microsatellite instability could not predict a histopathological response to neoadjuvant radiotherapy, but was a good prognostic marker for patients without lymph node metastasis after neoadjuvant radiotherapy.

The expression of chemokine receptors CCR6, CXCR2 and CXCR4 is not organ-specific for distant metastasis in colorectal cancer: a comparative study.

AIMS: The liver and lung are the organs most commonly affected by metastasis in colorectal cancer (CRC), and the interaction of chemokines and chemokine receptors (CKRs) plays an important role in the metastatic process. The aim of this study was to investigate the organ specificity of CKRs in CRC distant metastasis. METHODS AND RESULTS: Surgical specimens of primary tumours from 46 patients with metachronous distant metastases were retrieved retrospectively (20 lung metastases; 26 liver metastases). As a control, the records of 29 patients without distant metastases were randomly retrieved from our database, and their specimens were reassessed. The expression rates of CKRs, including CCR6, CXCR2, and CXCR4, were determined by immunohistochemistry, and were compared among the groups. The expression rates of CCR6 and CXCR2 were both significantly higher in the metastasis group than in the non-metastasis group (P < 0.05), but there was no statistical difference between the lung metastasis and liver metastasis subgroups. The expression of CXCR4 was not significantly different between the metastasis and non-metastasis groups. Multivariable analysis suggested that preoperative serum carcinoembryonic antigen level, CCR6 and CXCR2 were independent factors associated with distant metastasis. CONCLUSIONS: The expression of CCR6 and CXCR2 in CRC could predict metachronous distant metastasis, but they have no organ specificity for metastasis.

[Correlation between tumor cell proliferation and prognosis of primary cutaneous malignant melanoma in 127 patients].

OBJECTIVE: To investigate the correlations among Ki-67 expression, mitosis and other clinicopathological parameters of primary cutaneous malignant melanoma, and search for prognostic factors of malignant melanoma. METHODS: Totally 127 cases of primary cutaneous malignant melanoma were collected from Beijing Cancer Hospital. Immunohistochemical study for Ki-67 was performed, and the mitosis was calculated referring to "hot spot" method recommended by the seventh edition of the American Joint Committee on Cancer (AJCC) melanoma staging system. The correlations of Ki-67 expression, mitosis and other clinicopathological parameters were analyzed, and the survival analysis of all these risk factors including TNM and Clark level was conducted based on follow up data. RESULTS: The expression level of Ki-67 was associated with necrosis and Breslow thickness (P < 0.05). Mitosis was correlated with Clark level and Ki-67 expression (P < 0.05). Univariate analysis indicated Ki-67 expression level (P = 0.043), mitosis (P = 0.030) and TNM stage (P < 0.001) might influence the survival of patients. However, multivariate analysis showed that the TNM staging was the only independent prognostic factor affecting survival. CONCLUSIONS: The prognosis of patients with primary cutaneous malignant melanoma was closely related to the TNM staging at the fist examination. Ki-67 expression and mitosis are two important clinicopathological parameters of primary cutaneous malignant melanoma.

[Expression and prognostic significance of galectin-1 and galectin-3 in benign nevi and melanomas].

OBJECTIVE: To study the expression and prognostic significance of galectin-1 and galectin-3 in different melanocytic lesions. METHODS: The expression of galectin-1 and galectin-3 in 39 cases of benign nevus, 58 cases of primary cutaneous melanoma, 24 cases of primary mucosal melanoma, 69 cases of melanoma with lymph node metastasis and 8 cases of melanoma with distant metastasis were studied by immunohistochemistry and tissue microarray. RESULTS: The expression of galectin-1 and galectin-3 was higher in benign nevi than in melanomas (P < 0.01). The nuclear expression of galectin-3 was higher in primary cutaneous melanomas than in primary mucosal melanomas or melanomas with metastases (P < 0.01, respectively). The expression correlated with age of patients (P < 0.05), necrosis (P < 0.05) and survival time (P < 0.01). Clark's level also correlated with survival time in patients with cutaneous melanomas (P = 0.037). TNM staging was the only independent prognostic factor for melanomas (P < 0.01). CONCLUSIONS: The expression of galectin-1 and galectin-3 is decreased in melanomas. The decrease in nuclear expression of galectin-3 may represent a poor prognostic factor for melanomas. TNM staging is an independent prognostic factor which influences the survival time.

Surgery may not benefit patients with locally advanced rectal cancer who achieved clinical complete response following neoadjuvant chemoradiotherapy.

PURPOSE: We compared the long-term outcome of the watch and wait (WW) strategy and surgery in patients with locally advanced rectal cancer. PATIENTS AND METHODS: This prospective cohort study included 84 patients who achieved clinical complete response (cCR) after neoadjuvant chemoradiotherapy (NCRT). They were divided into the WW group (n = 58) and surgery group (SG, n = 26). Patients in the SG underwent total mesorectal excision. The study site was the Peking University Cancer Hospital. RESULTS: Eighty-four patients were included (58 and 26 in the WW group and SG, respectively). A total of 76·9% of the patients in the SG achieved pathological complete response (pCR) and 23·1% of the patients had a residual tumor. The total recurrence and metastasis rate was 15·4% (4/26) in the SG and 18·9% (11/58) in the WW group. There was no significant difference in the recurrence and metastasis rate between the two groups. In the WW group, 9 cases developed tumor regrowth during follow-up and underwent salvage surgery. The overall survival rate of the WW group (96·6% vs 92·3%) was not significantly different from that of the SG (P > 0·05). The WW patients also retained their anal sphincter function and avoided surgery-related complications. CONCLUSION: The WW strategy is a feasible treatment option in patients with cCR after NCRT. Surgery may not bring benefits to these cCR patients.

Correlation of diffusion-weighted imaging data with apoptotic and proliferation indexes in CT26 colorectal tumor homografts in balb/c mouse.

PURPOSE: To investigate whether the percentage of apparent diffusion coefficient (ADC) changes could be used as an imaging marker related to tumor cell apoptotic and Ki-67 proliferation index of tumors. MATERIALS AND METHODS: Mice bearing CT26 colorectal carcinoma tumors were scanned before radiotherapy, then divided into radiotherapy (n = 24) and control groups (n = 24). Diffusion-weighted imaging (DWI) and anatomic T2WI were performed on six randomly chosen mice in total from two groups at different timepoints after radiotherapy (4, 8, 12 hours, 1, 2, 3, 5, 7 days). After imaging, six animals were sacrificed at each timepoint and histological analyses were undertaken. ADC maps were calculated on a pixel-by-pixel basis using built-in software (Functool, GE). Regions of interest were manually circumscribed for all high-signal areas on lesions observed during DWI. The percentage of ADC changes were calculated at predefined timepoints and compared with the apoptotic and proliferation index from the histological analyses by using the Pearson correlation test. RESULTS: A significant positive correlation was found between the percentage of ADC changes of the viable tissue and apoptotic index. A significant negative correlation was found between the percentage of ADC changes of the viable tissue and Ki-67 proliferation index. CONCLUSION: Our results suggest that the percentage of ADC changes can be used as a measurement of cell apoptotic and proliferation index in colorectal carcinoma.

[Epidermal growth factor receptor gene mutations and clinicopathologic correlation in 309 patients with non-small cell lung cancer].

OBJECTIVE: To investigate the epidermal growth factor receptor (EGFR) gene mutation profile and related clinicopathological features in Chinese patients with non-small cell lung carcinoma (NSCLC). METHODS: Optimized oligonucleotide probe method was applied to detect EGFR mutations involving exons 18 - 21 using formalin fixed paraffin embedded tissue specimens of 309 NSCLC patients. The relationship between EGFR mutations and clinicopathological features were analyzed. RESULTS: The overall EGFR mutation rate was 34% (105/309) in this study cohort. Mutation rates in male and female were 30.4% (56/184) and 39.2% (49/125), respectively. The mutation rate was higher in patients less than 60 years of age, non-smokers and adenocarcinoma subtype than in their counterparts (P<0.05), with the percentage of 40.5% (87/215), 40.2% (51/127), 38.8% (78/201), respectively. The EGFR mutation types included exon 18 G719X mutation (5.7%, 6/105), exon 19 deletion (39.0%, 41/105) and exon 21 L858R mutation (55.2%, 58/105). In large cell undifferentiated carcinomas and squamous cell carcinomas, EGFR mutation rates were 22.2% (58/105) and 3/14, respectively. The overall mutation rate of exon 18 was low, but the proportion of its mutation was higher in squamous and adenosquamous carcinomas than in adenocarcinomas. CONCLUSIONS: There is a higher EGFR mutation rate in female, age of less than 60 years, non-smoker and adenocarcinoma among Chinese patients with NSCLC. Optimized oligonucleotide probe method is a sensitive and convenient method for the detection of EGFR mutations.

[Comparison of pathologic and clinical characteristics of young and old patients with advanced rectal cancer after neoadjuvant radiotherapy].

OBJECTIVES: To address the difference of pathologic and clinical characteristics of the young and the middle-aged and elderly patients with advanced rectal cancer after neoadjuvant radiotherapy. METHODS: A total of 252 patients undergoing radical surgery from January 2000 to January 2005 were included in this study. The patients were divided into two groups according to the age at diagnosis:young-patient group (< 40 years) and old-patient group (≥ 40 years). The pathologic and clinical materials were collected and the oncologic outcome was compared between the two arms. RESULTS: A total of 252 patients were included in this study, included 54 patients in young-patient group and 198 patients in old-patient group, respectively. There was no significant difference in gender, clinical stage and pretreatment serum carcinoembryonic antigen (CEA) between the two groups. However, the proportion of mucinous and signet-ring cell cancer was significantly higher in young-patient group (20.4% vs. 4.0%, P < 0.05), and furthermore, the proportion of pathologic stage later than IIIA was also significantly higher in the young-patient group (61.1% vs. 42.9%, P < 0.05). There was no significant difference in local recurrence rate between the patients who received neoadjuvant radiotherapy and those who did not in the young-patient group, whereas the difference was observed significant in the old-patient group (3.3% vs. 11.2%, P < 0.05). There was no significant difference in both the disease free survival and overall survival between the two arms (5y-DFS: 63.3% vs. 68.5%, P > 0.05; 5y-OS: 73.5% vs. 72.9%, P > 0.05). CONCLUSIONS: Rectal cancer in young patients has poorer histologic differentiation and more advanced pathologic stage, but the long-term survival is similar to that in middle-aged and elderly patients. The local control effect of neoadjuvant radiotherapy on rectal cancer in young patients still need to be further investigated.

[Pathological evaluation after preoperative neoadjuvant treatment in rectal cancer].

Preoperative neoadjuvant therapy of rectal cancer has been widely promoted, and postoperative standardized pathological assessment has gradually attracted widespread attention. Accurate pathological examination plays an indicating role in the diagnosis and treatment of rectal cancer, which can not only evaluate the effects of neoadjuvant chemoradiation and surgical resection, but also guide postoperative adjuvant therapy and assess the prognosis. Tumor regression grade (TRG) and TNM staging are the bases of routine pathological diagnosis of rectal cancer, and they are closely related to patient survival and prognosis. At present, TRG evaluation methods for neoadjuvant chemoradiation include NCCN, AJCC, Becke, Mandard, Dowrak/Rodel, MSKCC, and RCRG. However, there is still no universally accepted best standard. The commonly used classifications in practice are AJCC and NCCN TRG grading standards. The prerequisite for accurate TRG classification is a detailed and standardized pathological assessment, which includes both gross assessment of the specimen and microscopic examination. How to evaluate the therapeutic response to lymph node metastasis after neoadjuvant therapy and improve the assessment consistency among pathologists are the two major issues that remain to be resolved.

[Clinicopathologic analysis and expression of cyclin D1 and p53 of ovarian borderline tumors and carcinomas].

OBJECTIVE: To study the clinicopathological features and expression of cyclin D1 and p53 in epithelial ovarian tumors, and to investigate the correlation between pathogenesis of ovarian cancer and epithelial borderline tumors. METHODS: Fifty four cases of ovarian borderline tumors and 45 cases of ovarian carcinomas from the People's Hospital, Peking University were reviewed retrospectively. The clinical data and pathological findings were analyzed. Immunohistochemical study of cyclin D1 and p53 was performed in all 99 cases. RESULTS: (1) In borderline tumors, the age of patients ranged from 14 - 82 (mean age = 42.5) years. International Federation of Gynecology and Obstetrics (FIGO) stage of borderline tumors was stage I in 48 cases, stage II in 3 cases, and stage III in 3 cases. In ovarian carcinomas, the age of patients ranged from 26 - 80 (mean age = 53.5) years. FIGO stage of carcinoma was stage I in 6 cases, stage II in 8 cases, stage III in 26 cases, and stage IV in 5 cases. In follow-up of 54 cases with borderline tumors the 5-year survival rate was 98% and of 45 cases with carcinomas a 5-year survival rate of 51% was noted. (2) In 54 cases of borderline tumors, mucinous types accounted for 56% (30/54) and serous types accounted for 30% (16/54). There were 5 cases with micropapillary pattern, 3 cases with peritoneal implants, 3 cases with lymph node involvement, 6 cases with microinvasion, one case with intraepithelial carcinoma, and one case with mural nodules. In 45 cases of carcinomas, serous carcinoma was the most (49%, 22/45). The remainder included 3 cases of mucinous types, 8 cases of endometrioid types, 6 cases of transitional cell types, 3 cases of mixed phenotype and 3 cases of undifferentiated types. (3) Overexpression of cyclin D1 and p53 was observed in 31% (14/45) and 56% (25/45) of ovarian carcinomas, respectively. There was a significant association between p53 overexpression and tumor grade. In the borderline tumor group, 69% (37/54) had overexpression of cyclin D1 and 6% (3/54) had overexpression of p53. There were significant differences in expression of cyclin D1 and p53 between conventional serous borderline tumors and high-grade serous carcinomas (cyclin D1: 91% vs 26%; p53: 0 vs 58%). However, micropapillary serous borderline tumors and low-grade serous carcinomas showed remarkably similar expression of cyclin D1 and p53. CONCLUSIONS: Epithelial ovarian borderline tumors are distinct from ovarian cancer in clinical progress and prognosis, and histological types. Overexpression of cyclin D1 is common in ovarian borderline tumors and low grade carcinomas. And overexpression of p53 is more common in high grade ovarian carcinomas. Conventional serous borderline tumors are distinct from high-grade serous carcinomas in pathogenesis. Micropapillary serous borderline ovarian tumors may be closely related to low grade serous carcinomas.

Primary Ewing's sarcoma/primitive neuroectodermal tumor of the ileum: case report of a 16-year-old Chinese female and literature review.

BACKGROUND: Ewing's sarcoma (ES) and primitive neuroectodermal tumors (PNET) are closely related tumors. Although soft tissue ES/PNET are common in clinical practice, they are rare in the small intestine. Because of the absence of characteristic clinical symptoms, they are easily misdiagnosed as other benign or malignant diseases. CASE PRESENTATION: Here, we present the case of a 16-year-old female who complained of anemia and interval hematochezia. Her serum test results showed only a slight elevation of CA-125 and a low level of hemoglobin. Computer tomography and magnetic resonance imaging revealed a cystic and solid mass in the lower abdominal quadrant and pelvic region, which prompted suspicion of a malignant gastrointestinal stromal tumor of the small intestine. After resection, the tumor's histology and immunohistochemistry (positive for CD99, vimentin and synaptophysin) results suggested ES/PNET. Fluorescent in situ hybridization tests proved the breakpoint rearrangement of the EWSR1 gene in chr 22.Ultrastructural analysis revealed neurosecretory and glycogen granules in the tumor cell cytoplasm. CONCLUSIONS: Together, these data supported the diagnosis of a rare case of localized ES/PNET in the small intestine without adjuvant chemo- or radiotherapy. To our knowledge, this is the first report from China of a primary small bowel ES/PNET in the English-language literature. In addition, on the basis of findings from previous publications and the current case, the optimal treatment for localized gastrointestinal ES/PNET is discussed.

Use of a combination of CEA and tumor budding to identify high-risk patients with stage II colon cancer.

BACKGROUND: High-risk patients with stage II colon cancer may benefit from adjuvant chemotherapy, but identifying this patient population can be difficult. We assessed the prognosis value for predicting tumor progression in patients with stage II colon cancer, of a panel of 2 biomarkers for colon cancer: tumor budding and preoperative carcinoembryonic antigen (CEA). METHODS: Consecutive patients (N = 134) with stage II colon cancer who underwent curative surgery from 2000 to 2007 were included. Multivariate analysis was used to evaluate the association of CEA and tumor budding grade with 5-year disease-free survival (DFS). The prognostic accuracy of CEA, tumor budding grade and the combination of both (CEA-budding panel) was determined. RESULTS: The study found that both CEA and tumor budding grade were associated with 5-year DFS. The prognostic accuracy for disease progression was higher for the CEA-budding panel (82.1%) than either CEA (70.9%) or tumor budding grade (72.4%) alone. CONCLUSIONS: The findings indicate that the combination of CEA levels and tumor budding grade has greater prognostic value for identifying patients with stage II colon cancer who are at high-risk for disease progression, than either marker alone.

Depletion of p42.3 gene inhibits proliferation and invasion in melanoma cells.

PURPOSE: The p42.3 gene is identified recently, and the upregulated expression has been characterized in a variety of human cancers and embryonic tissues but not yet in malignant melanoma. In this study, we explored the role of p42.3 gene in the development of melanoma. METHODS: The expression of p42.3 was detected by immunohistochemistry staining of 261 cases of patient lesions, including nevi and melanoma, and its correlation with clinical pathological characteristics and prognosis was analyzed. Furthermore, a series of in vitro assays were used to investigate the biological function of p42.3 in melanoma cells. RESULTS: Immunohistochemistry staining showed an elevated expression level of p42.3 in melanoma compared to nevi (P = 0.001). Statistical analysis indicated that this high level was well correlated with patients' clinical stage (P = 0.045), but not with gender, age, clinical type, mitotic rate, and overall survival (P > 0.05). Moreover, in vitro assays showed knockdown p42.3 gene expression could inhibit the biological profiling, including proliferation, migration, and invasion of melanoma cells, and also affect PI3K/Akt pathway, MAPK pathway, and ß-catenin. CONCLUSIONS: This study suggests that p42.3, acting like an oncogene, is involved in the malignant transformation process of melanoma and may serve as a biomarker for diagnostic and treatment purposes.