recently proposed two-gap scenario 16,17 that superconductivity occurs in the nodal region in underdoped samples. Our observation indeed implies a close relationship between the occurrence of superconductivity and the existence of QP peak around the node. Here, it should be noted again that one can observe a nodal QP peak already for p ≃ 0 . 03 in the insulating LSCO. Thus, it seems that the doping evolution of the electronic structure is whether a QP feature appears near E$_{F}$ well above the LHB before a significant chemical potential shift occurs or not. So far, LSCO has been the only example that shows the appearance of a QP band before the chemical potential starts to shift in the lightly-doped region. It is an important question to ask which makes this difference between the different families of cuprates. It has been pointed out that the major difference in the electronic structure of the CuO$_{2}$ plane between LSCO and Bi2212 lies in the magnitude of the next- nearest-neighbor hopping t ′ within the single band description of the CuO$_{2}$ plane $^{18,19}$. The magnitude of t ′ is expected to decrease with influence of the apical oxygen on the CuO$_{2}$ plane $^{20}$, and therefore LSCO, which has the shortest Cu-apical oxygen distance among these cuprate families, is expected to have the smallest | t ′ | . According to the t - t ′ - t ′′ - J model calculation, a larger energy shift of the chemical potential with hole doping in the underdoped region has been predicted for larger | t ′ | $^{21}$, consistent with our observation that Bi2212 and Na-CCOC showed faster chemical potential shift than LSCO. Recently, the new interpretation of the ARPES line shapes of undoped and lightly-doped cuprates in Na-CCOC and LSCO was proposed $^{8,22,23}$, which took into account polaronic ef- fects because arising from strong electron-phonon coupling. The broad hump structure was successfully explained by polaronic effects. The similarity of the spectral lineshape between lightly-doped Bi2212 and Na-CCOC indicates that the polaronic scenario can also be ap- plied to Bi2212, too. Moreover, theoretical works reported that the phase separation, which occurs with suitable electron-phonon coupling strength $^{24}$, successfully explained the doping evolution of the electronic structure of underdoped LSCO, namely, the “two-component” behavior $^{25}$. The calculation also predicted that phase separation would be suppressed when the electron-phonon coupling becomes stronger and the system shows polaronic insulating state $^{24}$. This implies that Bi2212, Bi2201 and Na-CCOC have larger electron-phonon inter- action than LSCO and the different strength of electron-phonon coupling makes different doping evolution of the electronic structure in the different families of cuprates. 6