Timing of formation of the Hongdonggou Pb-Zn polymetallic ore deposit,Henan Province,China:Evidence from Rb-Sr isotopic dating of sphalerites

The Hongdonggou Pb-Zn polymetallic ore deposit, located in the southwestern part of the Luanchuan Mo-W-Pb-Zn-Ag polymetallic ore mineralization in Henan Province, China, is an important part of the East Qinling metallogenic belt. The orebodies in the deposit, which are vein, bedded and lenticular, are mainly hosted in the syenite porphyry, and formed within the carbonate and clastic rocks of the Yuku and Qiumugou formations partially. The genesis of the deposit has previously been argued to be of hydrothermal-vein type or of skarn-hydrothermal type. In this study, we report the results of Rb-Sr isotopic dating based on sphalerites from the main orebody of the Hongdonggou Pb-Zn polymetallic ore deposit, which yield an isochron age of 135.7 ± 3.2 Ma, constraining the timing of mineralization as early Cretaceous. The age is close to those reported for the Pb-Zn deposits in the Luanchuan ore belt. The （87Sr/86Sr）i values of the sphalerites （0.71127± 0.00010） are lower than that of terrigenous silicates （0.720） and higher than the mantle （0.707）, suggesting that the metallogenic components were mainly derived through crust-mantle mixing. Combining the results from this study with those from previous work, we propose that the Hongdonggou Pb-Zn polymetallic ore deposit is a hydrothermal-vein deposit associated with the early Cretaceous tectonothermal event, and the mineralization is controlled by NW- and near EW-trending faults in the Luanchuan Mo-W-Pb-Zn-Ag polymetallic ore concentration belt.

The prognostic role of circulating tumor DNA across breast cancer molecular subtypes:A systematic review and meta-analysis

Objective:Circulating tumor DNA(ctDNA)is increasingly being used as a potential prognostic biomarker in cancer patients.We aimed to assess the prognostic value of ctDNA in different subtypes of breast cancer patients throughout the whole treatment cycle.Materials and methods:PubMed,Web of Science,Embase,Cochrane Library,Scopus,and clinical trials.gov databases were searched from January 2016 to May 2022.The following search terms were used:ctDNA OR circulating tumor DNA AND breast cancer OR breast carcinoma.Only studies written in English were included.The following pre-specified criteria should be met for inclusion:(i)original articles,conference abstracts,etc.;(ii)patients with breast cancer;(iii)ctDNA measurement;and(iv)clinical outcome data such as recurrence-free survival(RFS)and overall survival(OS).The random-effects model was preferred considering the potential het-erogeneity across studies.The main outcomes are ctDNA detection rate and postoperative long-term outcomes(RFS and OS).Results:A total of 24 studies were screened.At every measurement time,the ctDNA detection rate of the HR+subgroup was similar to that of the HR-subgroup(P=0.075;P=0.458;P=0.744;and P=0.578),and the ctDNA detection rate of the HER2+subgroup was similar to that of the HER2-subgroup(P=0.805;P=0.271;P=0.807;and P=0.703).In the HR+subgroup,RFS and OS of ctDNA positive patients were similar to those of ctDNA negative patients(P=0.589 and P=0.110),while RFS and OS of the ctDNA positive group was significantly shorter than those of the ctDNA negative patients in the HR-subgroup(HR=4.03,P<0.001;HR=3.21,P<0.001).According to HER grouping,the results were the same as above.In the triple negative breast cancer(TNBC)subgroup,the RFS and OS of ctDNA-positive patients was significantly shorter than of the ctDNA negative patients before and after surgery.Conclusions:ctDNA was more predictive of recurrence-free survival and overall survival in the HR-subgroup than in the HR+subgroup,and the same result was showed in the HER2-subgroup vs.HER2+subgroup.The prognosis of the TNBC subtype is closely related to ctDNA before and after surgery.